This guide assumes that you're choosing to play this survival game without the survival and with severely nerfed wraiths. Maybe you've checked out some more general guides, seen reviews or discussions that mentioned certain things. You'll also get comments about dangers etc. in-game. Not all of those things are applicable in "Peaceful Mode".

You won't have to worry much about weapons or food, and you should be fine exploring during the day and enjoying the scenery. You won't have to bother with crafting extra protections in the more advanced biomes, just bring a couple of relevant consumables or don't stay so long.

Essence can be a concern in the beginning, as you need it for sigil gates, springs and so on. But you were probably going to plant a lot anyway. The skill tree is a mixed bag with some features that are irrelevant for us, but that unlock useful ones further down the branch. The crafting menu is hiding some gems behind functional structures that we won't need.
I'll also talk a bit about the main quests and when you might want to do them - or how many of them - and how to avoid outcomes that a number of players were very unhappy with.

Just a few comments on what the different elements do and how I experienced them. Ignore this if you want the standard "Peaceful Mode".

Food/Water Consumption: At "Peaceful" Mode's standard 33%, food was no challenge at all for me and water only a few times. You can go lower, but then it would probably feel a bit pointless to grow any food...

Recovery Speed: I guess this covers health and possibly essence and/or mana. I just left it untouched.

Damage Dealt: I turned this up to the max of 400% to get ridiculously OP in my first playthrough as I really don't want to deal with combat.

Food Toxicity: Not much of a concern really.

No Turning Back: This locks the difficulty settings for this save once you start the playthrough. I don't know why you'd want to do that to yourself.

Fatal Poison: The default (even in normal mode) is that poison from both food and environment reduces your health, but doesn't kill you.

Retain Items On Death: Default in Normal Mode is that you lose your inventory and its location gets marked on the map.

Limit Rebirth: I don't think we'll need to touch this.

Spoilage Speed: I changed this to the minimum after playing for a bit because I find decaying mechanics annoying and stressful. It also took me way too long to figure out how to get a preservation basket.

Day/Night Length: I like to take my sweet time, so I ended up setting my days to max. and nights to 150%.

Buried Item Drop Rate: I didn't find it necessary to change this.

Spawn Hazards: This is for tumbleweeds and dust devils (tiny storms) that damage and potentially destroy your plants and structures. I don't know why you'd want those activated, except maybe having a better reason to build walls and all that.

Spawn Dust Storms: If toggled on, they start appearing after a certain point in the story. They can be very destructive for your gardens and kill your character. Both the game and some players talk about more items appearing (respawning) after these storms, but when toggled off they'll respawn at the same rate.

Hazard Damage: From what I've gathered, this applies to all types of damage to your plants, your structures, and your character. Tumbleweeds, dust devils, dust storms, wraiths, even harmful effects from biomes. The "peaceful" default wasn't really a challenge, but I didn't like the poison blinking so I turned it off at some point during my first playthrough.

Fall Damage: Pretty straightforward. I turned it off during my first playthrough because it just slowed me down lol.

Plant Growth Speed: I've never touched this one. I like singing for and fertilising my plants, and if you crank this up then they probably also get old and eventually die faster.

These are mostly straightforward and I didn't change any of them. I'm really useless at combat stuff, but these settings allowed me to be clumsy and disoriented a lot.
Corruption spread is about the spread of the black wasteland that wraiths and their outposts cause.
Attack frequency is about attacks on your oasis - some farm them for scrolls and other items that defeated wraiths drop, but I was fine without them. Note that this setting doesn't always seem to work properly - I've been attacked multiple times in multiple places unrelated to the main story, including my home oasis (haven't noticed any damage).

Not a complete list (yet?), but these are the early-mid game skills or discoveries that the ghost memories can teach you, and how relevant I'd say they are for Peaceful+ difficulty mode. The in-game descriptions are often pretty vague or incomplete - I do mention why you'd want to choose a thing, so if you want to be completely surprised by items and features related to gameplay then this section is not for you.

- left branch -

Adornments: One of the first options you're likely to want - it lets you make a simple wooden ring for more inventory slots so you can collect more different seeds and materials.

Fine Carving: pretty unnecessary trinkets, but unlocks access to Artisan which is much more useful. Skating up sand dunes might be cool, but at this point you can probably fly and your space for trinkets is very limited. I guess it's useful if you want to thoroughly explore the starting biome before venturing further.

Artisan: lets you craft a bracelet that's super useful for gardening purposes - the pearl bracelet that lets you move trees.

Jeweller: I don't think any of these are relevant for us.

- middle branch -

Carpentry: Unlocks wooden walls and gates, and bridges. Bridges can be useful, the rest only has aesthetic value for us. Also unlocks storage upgrade to big basket.

Construction: Unlocks wooden lamps, and the ability to upgrade wooden paths to stone paths and wall foundations to stone or cement walls.
The lamps require ingredients from the southwest of the map. The white ones make quite a difference for visibility at night, the coloured ones mostly look pretty. I've also used them for easier orientation in my oasis.

Architecture: Unlocks metal lamps that require a material from the northwest of the map. Neat if you like the style, or if you'd rather forage for the fancy metal than the fancy wood. Also unlocks fancy cement upgrades for the planter.

- right branch -

Flint Tools: boring, but makes a difference if you've found digging and using your sickle tedious.

Obsidian Tools and Starmetal Tools: same as above

Mirrored Blade: I don't know why you'd want to choose this, except for a certain achievement.

Sigil Stones: The arcane tree's base skill. Extremely useful early on for the gates, try to find an arcane ghost for it as soon as you start exploring. Also unlocks storage upgrade to preservation basket.

- left branch -

Ornate Sigils: None of these are really useful for us, except possibly the Flowering Sigil for more acorns (plus it's nice thematically). Oh, and picking it before going to Gleb's temple for the story quest will make your life easier. Unlocks access to Aura Tuning.

Aura Tuning: Very useful once you get the Feather Bracelet for better flying in addition to the inventory ring.

Aura Alignment: Very useful in combination with a certain bracelet unlocked by Artisan (Survival).

Mystic Sigils: Meh. If you really want faster plant growth and even bigger harvests than you can get by improving soil and singing for growth, this lets you upgrade the Flowering Sigil.

- middle branch -

Crystal Clarity: Meh, I'd rather put spiritual memories into springs and the arcane ones towards Symbiosis first.

Ancestral Lore: Sounds exciting, but it's really just 1 food and 1 medicine and you're probably finding more of them in chests and digging spots than you'll ever need.

- right branch -

Seed's Power: I can't see much use for it, but it's a step on the way to the very useful Symbiosis. It also unlocks soothing poultice and glowing infusions at the crafting table, but you probably won't need them either.

Adaptation: Neat gardening skill (interact with a plant to change it to a different cultivar that you've already discovered), and it unlocks access to Symbiosis.

Symbiosis: Gives you access to the root sigil, one of the best things in the game for peaceful gardeners. It can be built as an upgrade to a basic sigil (construction menu) and helps distribute water to plants that are otherwise too far away from a spring. Functions like a plant and needs to grow before reaching its final radius - you can sing for it to speed up the process.

Life Shaping: Top notch gardening skill. Lets you put plants into hibernation mode so they stop throwing seeds all over the place, don't grow elderly so fast, and use less water. Also helps with completing your plant collection.

Song of Growth: Nice and somewhat useful base skill, especially if you're impatient. Watch your essence in early game though - you'll also need it for things like sigil gates and cleansing springs.

- left branch -

Water Seeker: Excellent, lets you fix water sources and grow plants outside of your oasis. Less necessary for us than for normal mode+, but very satisfying.

Waking Spring: Lets you cleanse the springs in other biomes, including the one where being able to refill your water bottle is extra useful.
Cleansing springs also requires life sparks that you can get from spirit darters (flying creatures only visible at night time in the wild).

Wellstones: Very useful if you want to bring water to an area without natural springs (you can chain several of them, more after upgrading your spring).

- right branch -

Animal Empathy: Cute skill that you need if you want to use Waking Spring to cleanse springs. You'll be able to "trade" with spirit darters and invite them to one of your gardens. They'll stay visible during day time once brought to a spring and you can get one life spark per day from each of them. Also lets you befriend frogs and the trickster pangolin.

Song of Rebirth: A good way of wasting your precious acorns in early game. You're going to get a quest that lets you mass-revive some areas so maybe wait a little before using this much.

Companions: This adds the ability to give essence to frogs, which increases their inventory and makes them glow and easier to see. Apparently it also lets you choose alternative tree seeds for creating life sparks.

Without hazards or (hopefully, if not bugged) wraiths haunting your gardens, you can just focus on making everything look nice and lush.

Garden frenzy vs. story quests?
You might have seen people recommend that you don't do much gardening before finishing the story. One of the reasons for this - and how relevant it is for us - can be found in my last chapter.
The other reason is that the early-game tools are wildly inefficient. If you want to make very minor and precise adjustments, however, that's actually getting more difficult with the upgraded spade (let alone a certain other tool) - and there's no way back from the upgrades. They'll affect a larger area, whether you want it or not.
Personally, I spent LOTS of time gardening and some time digging to direct water flows and create small streams before getting far with the story, and I don't regret any of that time. I enjoy inefficient digging more than focusing on quests without getting side-tracked.

I won't cover water distribution and restoration techniques here as this has already been done elsewhere (MB's guide seems solid, for example). What I haven't seen is an overview with pictures of the structures you can build - decorating is unfortunately quite limited in this game, but there's more variety than what you can see in the crafting menu.

First of all, it took me way too long to find out that I could build stone paths - after wasting wood for them... You have to build a wooden path and then interact with it. This is available after choosing Construction from the survival memories.



Planters
You can upgrade them!


The regular and wooden planter that are available right away; cement, pink cement, and temple planter are unlocked through Architecture (survival memories).


Walls
You can build them from the wall foundation, and there are more upgrades hidden behind the first ones.

The drystone wall can be built on the foundation after choosing Construction (arcane memories). It can be upgraded to a mortared stone wall that's just higher and looks a bit weird with the gate.
The wooden wall can be built from the foundation after the earlier Carpentry memory, but can only be fortified invisibly. The pic shows what it looks like when two are joined to form a corner.
The cement wall is another choice from the foundation (unlocked by Construction) and opens new possibilities:
glass deco with window holes that can be closed with more cement, and a mosaic wall that kind of matches with the glass deco one and can be upgraded with a window.


The sunburst hedge and thorny hedge are also walls, and logically you have to start with a wall foundation in order to build them (: Unfortunately, the sunburst hedge can only be yellow. The thorny hedge looks about as pretty as barbed wire - until you let some moon glory climb on it! (This doesn't seem to work with the sunburst hedge for some reason.) These are unlocked through Symbiosis (arcane memories).

Gates
The wooden gate can be "upgraded" to a door, the round gate... it's complicated.

The wooden gate (requires Carpentry) and the arched door it can be "upgraded" to. The round gate (requires Construction afaik) can be upgraded to a cement gate, and/or you can add a wooden door. The cement gate can be upgraded to a pink or white painted cement gate, and you can still add a wooden door if you haven't. The wooden door can be upgraded to either a fancy double door or a windowed door. So you can have any combination of round gate and door variations. I think.

Lamps
There are wooden lamps (requiring Construction) and metal lamps (requiring Architecture). Each set comes in 3 different sizes and can be lit in white (most practical) and 6 different colours :)


Special decorations
Again it took me embarrassingly long to figure out that I could build statues by building a statue base and then interacting with it... The statues are all miniatures of the tall ones that you should be familiar with by the time you unlock these. Gleb's is special, because with enough spiritual ghost memories (Song of Stones) it will let you craft a few natural features:

There don't seem to be variations - I always got the exact same deadfall, boulder, etc. The salt pillar is huge! (I included a pic of the statue base because otherwise the formatting got messed up for some reason)


Sigils
You may not need most of them, but some of them are quite pretty:
From left to right: Flowering, Sun, Moon, Flame+Searing, Root, Sorceress, and Spinebomb sigil. Flowering sigil can be upgraded to Fertile sigil, but I didn't want to go searching for more knotwood again...


Items
Some of the items and consumables that you can forage, loot or craft look quite cool. If you drop an infusion or elixir (after jumping on one of the tables that you'll encounter, for example) it actually shows up as a glowing bottle. You can also put down cups of fallenstar tea that you can make at the upgraded ancestral altar until they decay.

If a tree grows in your forest and no one is around to see it, does it make a sound? No, wait. Anyway, you might be interested in screenshots without the UI getting in the way!
Two options:
Photo mode (has to be selected from the menu? I don't know of any shortcut) lets you show or hide your character and do all kinds of neat stuff. Except hide the photo UI so you can take a screenshot to share on Steam. You could upload it as "artwork".
F11 is the secret (?) key to hiding the UI completely. Except when in photo mode, for some reason. You can still walk or fly around until you've found the best view, then press F12 for a UI-free Steam screenshot. I also use this key quite a lot to just walk around and enjoy my gardens without getting interaction prompts all over the place.

This section is for players who want to get through the story smoothly and/or are wondering how prepared they should be combat-wise. I'll keep the titles a bit vague to minimise spoilers for those who are sensitive to that kind of thing. I'm assuming you're playing on the standard map - if not, Southwest and Northeast might be switched.

The starting biome
Nothing much to say here, I think? Follow the instructions and you should be fine. I was able to one-shot all the wraiths with my basic copper mirror even in my new playthrough without the damage boost from the custom settings.

The Southwest
I found the wraith outpost thing really confusing. What you do is, you follow the pink "comets" again and they'll lead you to outposts that have a huge conch in them for whatever reason. You activate the conches and then run around to evade the wraiths that spawn while staying in the blue circle. Defeating the wraiths is pointless - they don't drop anything and keep spawning until a smaller blue circle has reached the centre of the outpost and... you'll see what happens.
Don't worry about the rest of the outposts for now - you won't be able to destroy them until/unless you finish a late story quest (giving Gleb's gift to Arx for an upgrade).

With my character's damage dealing at 400%, I barely got a scratch during the temple battles. In the unmodified "peaceful" mode with just the basic copper mirror, I drank one infusion. Investing ghost memories in an upgrade would have made things smoother and quicker.

Note that - as is common in this game - you need to talk to the deity several times to get optional quests/progress. In my unmodified-"peaceful" test playthrough, I didn't get notified of the requirements for the final upgrade of the gift, and it didn't show up during interactions until I had all the ingredients. I could see them in the quest list (pressing J).
Another thing you may wish you'd noticed earlier: at some point during this, you should also be able to craft the Feather Bracelet that further improves things.

The Northeast
Even if this quest will get you the more useful gift for gardening, it's extremely helpful to have finished the Southwest thing before doing this one.
It took me a while to figure out how to progress here, and I actually stumbled upon it by chance. You follow the comets once again, but then there's a white ghost on top of the city wall that you need to talk to. They'll send you to a place that I found difficult to locate - you can either take an elevator from the middle of the building behind the gate (that I hardly ever manage to find) or enter directly from the lowest level. There's some combat and again a mirror upgrade (or more than the standard-"peaceful" damage dealing in the settings) would make it easier, but it worked out fine.
The temple part was an unpleasant surprise because you're on a timer. I hate timers. Felt stressful the first time around, but there's really no need to worry about lots of defenses even in regular "Peaceful" Mode. I just built 1 worker bee and 1 soldier bee sigil at the pillar the quest directed me to. I turned the sigil stone that was there before into a Flame Sigil (needs the Ornate Sigils unlock) and moved it later. The soldier bees and the Flame Sigil did a lot of the work, and I could still one-shot wraiths with just the basic copper mirror.

The Northwest
This one is deliberately confusing, but I had less trouble with it than with the other ones. Just because you've been there before and there was nothing, doesn't mean it can't be there now. Combat was easy enough with my OP damage dealing from the settings and fully upgraded mirror, I might check it out in regular "Peaceful Mode" later.

There's another one
This one should be easy enough if you've done a lot of exploring, and there are no dangers to worry about IIRC.

The last one(s)
Sounds way scarier than it is in "Peaceful Mode", although it is by no means peaceful. I didn't have to bring any supplies as advised, nor were my preparations in a certain location necessary. I did have a fully upgraded mirror and all the passive buffs from "secret" memories.
I did a backup save just in case and went through the battle several times. The funniest thing was when I just let my network of flame/searing and cactus sigils do the entire work. Basically, Sellan was killed by a cactus.
More info in the first part of "Avoiding sad events".

This game doesn't have multiple endings as such, but there are two things that can happen that a lot of players didn't enjoy one bit:

Chances are you've seen people upset about getting their oasis garden destroyed at the end of the game. You do get a perfectly clear warning about this with unlimited time to prepare.
I've gone through that scene several times now, with no or minimal harm done. This is what happened and how I'd prepared:
After destroying the Tree, I got auto-teleported back to my oasis. While Vidyas was talking, a bright red symbol appeared on my compass and map. So the first time around I ignored the Vidyas ramblings and flew over there. As recommended by others, I used the time needle to slow him down (rinse and repeat when he manages to get out). When his shield dropped, it was a piece of cake to defeat him. We hadn't even reached my actual oasis.
I had already built flame/searing and cactus sigils that covered basically all of my oasis though, and done a backup save, so I was going to see how effective they'd be. Turned out I didn't have to do anything at all - I just watched the sigils shoot both wraiths and eventually Sellan. Some plants were mildly damaged, one dune grass died but was auto-resurrected in the aftermath.
I also suspect that setting hazard damage to 0 in the difficulty settings means you don't need to worry about this at all, planning to test this later - When I tried to test this, I was surprised to see a bit of damage. When I double-checked later, it turned out that the settings had reset themselves to standard "Peaceful" Mode at some point (I'm 100% sure I saved 0 hazard damage before loading the save). Maybe I'll do more research later.

And then there's another thing that has been criticised a lot, considering the low percentage of players who got to that point. It almost certainly isn't the kind of vibes that players seeking a peaceful experience would want.
You can avoid this outcome by not completing the optional restoration quests for all 4 biomes. Otherwise, you can sort of avoid it: If/when a certain deity asks you to talk to them at the end of the credits or after restoring all biomes - trust me, just don't. Forget that they ever asked. Or don't trust me and read what happens:
Naia dies. Without any explanation. Her statue crumbles. Vidyas has 3 lines to say about it (almost like "Yes, very sad. Anyway"), then it's all back to business as usual. You can even still craft life flames etc. at her broken statue.
It should be safe to interact with that deity's statue as long as you don't "pray" for that special conversation.
For me this happened at the end of the credits and completely ruined the ending. I'm trying to pretend that it didn't happen, I'm planning to load a backup save, but I can no longer enjoy my beautiful creations as much as before.

Finally, you can avoid both of these things AND a bunch of combat by just not doing the final quest. If you just want to restore the land and/or make things look nice (which I find OH SO satisfying!), it really isn't needed. You'll most likely want the quests + gifts by the first 3 deities. Depending on how ambitious you are, getting all the gifts and upgrades is useful. The finale only gives some story closure, but also, well... The above-mentioned addition to the ending was not the kind of closure I wanted. Just ignore that bit and create your nice gardens.

~