All skills exp gained by the actions:

• Weapon attack
  
• Use the ability
  
• Craft
  
• Build
  
• Salvage
  
• Other interactions

Various skills, like adventuring, leadership or athletics, have their own way to gain the exp. But the most os them can be defined as a combat or crafting ones

The weapon skills usually gain +1 exp by the attacking enemy and +2 exp for using skills. So obliviously the best way to attack the enemies with equipped weapon for 1 damage while they will do the same for you.
Either of stats improves the damage of weapons and your training punchbag will die faster
The thing with thorns is oblivious, to avoid damage. Dodge is bad because your character will move to another tiles that prevents you from the clicking the enemy.
The tools are doing the best duty there. Knife, scythe for polearm, common axe for chopping trees, short or bone sword, flail, crude bow.
Your first points into endurance will help you a lot. Willpower will help against magic attack for a little. But the best way is obtain the equipment with a lot of physical resist as soon as you can. Such as copper armor set, bracets from the cotton cloth, gorilla fur leather equipment.

The best punchbags for the skill gain are animated gems which spawns in the high mountains biome. They will not fight back. Drawfs are great too for this if you got enough of physical resist. They are spawning at the mountain regions and in the peaks.
The kangoroos from savanna are great too, they have a high physical resist but can damage you.

The way to gain is just to use the skills, regardless you damage the target or not. So there is no punch bags needed for the most of them. That's why Intellegence is not restricts you from improving the skills as Strength or Dexterity do for the weapon skills. The strategy there is using the ability with the smallest cooldown. And you can reduce the cooldown by some utility modifications, such as from 15 axe skill(-2 turns cooldown), 40 athletics (-4 turns cooldown) and from the variety magic mod (-6 turns cooldown and +5 stamina cost) at 45 skill.
Thats why you would be interested to unlock those modifications first.
Some of the single enemy damage abilities can be used on tiles instead enemies.

More details on the skill details

The three main methods for gaining exp to those skills are salvage, craft and build.
But usually those skills are questionable, because you will spend your skillcap on them but cannot gain stats from them. And you can always ask for craft the things to the NPC. Except building.
Unfortunately. The hardest part for the most crafting professions are gaining the first level, because the only way to get it is salvage. The best way to train it to raid point of interests of the human like enemies, like fisherman village. Some of the materials, such as firewood, embuing goods and cloth, are salvagable too. High Intellegence will help you to get materials from the goods.
The crafting system is quite complicated In Soulash 2.
The exp gain from craft depends on quantity and quality of the resources. For example, common item give +1 exp, green +2, blue +3 and so on.
That's why you will keep interested to spend a big quantity of magic ingredients from imbuing for it instead selling them.
In that way you will gain more exp
Quality wood is easy to find and can be harvested at large quantities. The gems and metal is rare, so you will prefer to use the bones instead. For large quantities of wood you can gain floramancy skill and unlock the tree bending at 15 floramancy skill level.
Intellegence is the best helper in crafing because it's reduces the time for craft.
The building system works same as a crafting one, some buildings requires more than 5 resources but you cannot use the magical ingredients for it.
Try to build at the tiles on your sight, your character starts to spend the time for building automatically
Party members are trying to support you with building but better to send them far away.

Adventuring is the skill which you will interested to level up first, because it's unlocks a lot of good features, like:

• Fishing pole at 12 lvl, the unlimited source of food
  
• Smelting ignots for later use or more profit
  
• 1F map reveal at 40 level
  
• +10 inventory slots at 45 level
  
• Multitool at 48 level
  And a lot more
  
  
  Base rates:
  • Craft: 1 exp
    
  • Resource discovery: 3 exp
    
  • Location discovery: 5 exp
    
  • Location details discovery: 10 exp
  
  
  Ways to train:
  The simple one is travel on global map and discover the points of interests.
  Especially this works well in maps with large amount of cities after passing 100+ years, but unfortunatelly the time in travel passes to fast and your character will get older. Be careful about your food and water.
  
  Crafting staffs.
  This way is quite boring, but effective. Go to boreal tundra to get rare woods such as pine or cedar. You will probably get the needed leven by discovering the points of interests by the way. Leftover firewood can be salvaged for training carpentry as well.
  
  Discovery.
  The most funny way to improve it.
  The most easy discoveries are:
  
• Fell the tree in jungle. Tundra have the uncommon trees as well.
  
• Fishing until you get some fish and then salvage it
  
• Mine the rock in various mountain biomes except the peaks
  
  Smelting.
  Works if you already unlock some reciepes. The best biome to find the ore is low mountain biome. There is 1 to 4 mountains in the local map and usually 2 or more diposites are spawned in there, such as copper, tin, iron or coal.

The skill which is handsome for the sowing the seeds and cooking.

• Higher level unlocks rarer types of seeds to sow, same as crafting the food which temporary buffs your stats.
  
• Ability to watch the shortage of food in the settlements
  
  Rates
• Craft: 2
  
• Milking and shearing: 1
  
• Gather crops:1 per resource
  
  Ways to train
  The best way to train is buy the flail with scythe and discover grassland biomes for wheat. Wheat can be salvaged into a seeds and hay. You can mill the seeds for making a flour as you wish. Grinds together with tailoring

The hardest crafting skill. This skill unlocks the armor which crafted from metal. leveling up this skill will unlocks the more gear, especially shield with the highest parry rate and emperor armor with the special skill.

• Craft and update:1
  
• Salvage:2
  
  Gaining level
  The first level is gained by salvaging stuff. Dwarfs are have the best gear to salvage, but they can be nasty for beginners. And there is no easy points of interests with the enemies which dresses the armors. Only few of humans wears the metal shield and that's it.
  After gaining your first level be ready to spend a lot of metal to improve it until you unlock the clogs. Later on you can craft scale stuff
  Using the magic materials from imbuing is nesessary. They are cheaper than the metal.
  Try to craft the items from the bones instead.
  26 lvl - Moccasins which uses 1 leather and 2 bones
  31 lvl - Bone Greaves which uses 3 bones and 1 leather
  34 lvl - Scale shield which uses 2 shell, 1 leather and 1 wood
  37 lvl - Scale boots which uses 1 leather and 3 shell
  39 lvl - Scale legs which uses 2 shell and 2 bone
  40 lvl - Scale armor which uses 4 shell and 1 bone

Awesome skill that gives you various bonuses as well as a stats, especially

• +20 weight limit
  
• Sprint. -0.3 moving speed Escape ability
  
• +max hp bonus
  
• Second wind ability, whic heals 500hp and 100 stamina, but with big cooldown
  
• No damage from the fall
  
• -0.10 moving speed utility for skills. Best ability add it with long buffs such as regeneration from floramancy.
  
  Exp rates
• Use ability: 2
  
• Drag: 5
  
• Throw: 3
  
• Climb: 2
  
• jump down: 2
  
  The way to train
  The first skill level is the most painful as others in different ways. All as you can, just up into stair and fall down from the cliff, but watch out for your HP.
  This way to gain exp works at all levels and gives exp pretty fast, so don't miss your opportunity on safe region from the smacking your face from the cliff.
  After getting no damage from fall you can get 50 level of the skill easy
  
  Use drag ability as soon as you unlock it
  Just fell down a tree and right click at the log, then pick "drag". And your skillgain will go into skyrocket until you get athletics level 5.
  
  Throw
  After that you can throw your log at the neighbour tiles. Remember, the mass of the throw projective must be more than 40. This way is quite boring and grindy, but it's nessesary for getting the first ability and weight limit bonus, which are worth for it
  
  Using ability
  After unlocking Sprint you will want yo use it everywhere. The moving animations depends at the moverment speed so the skill will make exploration faster. The most comfy way to get the skill.

The axe fighting skill which gives a lot of special moves as well as stats points.

• Early -2 turn utility skill modification which is handy for the most other skills.
  
• Focused on damage
  
• Knockback immunity at 36 level
  
• -50% time for cutting trees at 3 level
  
• Ability to wear 2 handed weapon in both hands at 48 skill
  
  Exp Rates
• Attack: 1
  
• Ability: 2
  
  Way to gain exp
  The best way is typical for weapon skills. Take the axe skill weapon with the poor attack, a hatchet for example, and attack the enemies which makes 1 damage to you. You can also use the rage ability as you needed
  

Used for building various tiles and furniture as wall as for craft the bows or elven armor.

• Unlock spinning wheel building at 20 skill, which is nesessary for some buildings
  
  Exp rates
• Craft: 1
  
• Salvage: 1
  
  Way to gain exp
  The way is quite simple. Get the wood, craft into firewood and salvage it into common wood again. A lot of firewood you can get from the borea forest biome. With thousands of wood materials this skill is trained really fast. Crafting of firewood don't required a crafting station. Tree bending ability from lvl15 floramancy will help to improve this skill as well.

The ability to build the things. Useful mostly for the building the things. Required for the build settlements.

• Skill is nesessary to build the settlement buildings
  
• Unlocks the companion slot at level 40
  
  Rates
• Craft: 1
  
• Settle: Instant level to 1
  
  Ways to gain exp
  Just get a lot of wood and craft. Works best with the carpentry skill because you can salvage the firewood. The borea forest biome nearby is recommended but not really. You can always make some wood with floramancy skill
  
• The first level is gained by the making the settlement.
  
• Build and destroy the storage unit until you unlock the mill
  
• Build and destroy the mill
  The most of things that required to the settlement will unlocked at 28 level.

The Ice and water related magic and a lot of ability points

• Automatically restores the thrist when getting wet
  
• Various ways to getting wet
  
• Ice/water related attacks
  
• Freezing things
  
• Walk on water passive at 44 level, which allows to travel at the ocean without boat
  
• 50% fire resist
  
  Exp rates
• Ability: 2
  
  Ways to gain exp
  Unfortunately there is no easy ways to gain exp. All abilities have a cooldown, but you can target the tiles with HP with your first spell.
  
  Beware! There is no way to get first exp! If you not choose the 5 level bonus for this skill at beginning or get the cheat/mod - the skill wil be locked forever

The skill which gave some nature attacking abilities which are aimed on the poison and thorns.

• Awesome tree bender ability, especially for crafters. That skill will used instead chopping down the trees for bigger wood gain, expecially for the rare wood types. Also can used on apple, banana, mulberry and date tree for getting another yeld without removing a tree. This action can be forbidden in same settlements.
  
• Immunity to poison at 15 skill
  
• Tree spawning for gaining a common wood without changing a location
  
• Thorns and thorns crit, can ruin the weapon skill grind.
  
  Exp rates
• Ability: 2
  
• Tree bender production: 2
  
  Skill gain
  This skill is hard to get until lvl 15, because you need an enemy target to use the ability.
  After unlocking the Tree wall ability you can chop down them before they dissapears and get free wood.
  
  Beware! There is no way to get first exp! If you not choose the 5 level bonus for this skill at beginning or get the cheat/mod - the skill wil be locked forever

The skills that gives you abilities to use with a crossbow same as abilities to hunt down the animals.

• Track ability which can help you to find the creatures.
  
• Two companion slots
  
• Ability to tame the pets, which is helpful for building the ranches.
  
• Passives that boosts pets
  
• More salvage from the fish/corpses
  
  Exp gain rates
• Attack: 1
  
• Ability: 2
  
• Track: 1
  
• Tame: 20
  
• Pet: 1
  
  Ways to gain the exp
  First at all, attacking the enemies with bow, but there is a lot of the arrows required. After unlocking the ability you can use it when traveling safely in the local map. At other hand you can pet some animal in the city.
  Spamming sense life works to improve that skill without wearing a bow
  At highest levels you can tame and free your pet to gain a lot of exp.

The skill that helps you to craft various magic ingredients for other craft

• Can be crafted almost from everything
  
• The crafted goods can be sold for wealth
  
• Helps to improve another crafting skills
  
• New metal type
  
• Easy to level
  
  Exp gain rates
• Craft: 1
  
• Salvage: 2
  
  Ways to gain the level
  For taking the first level you need to salvage almost every piece of the jewerly or magic ingredients.
  After that you need a few pieces of the cloth material. You can gain it from the shearing sheeps or from the gathering the wheat. And you can craft 2 rings from the cotton and equip it for additional physical resist.
  Craft a lot of engridients from the wood. The best material is the maple and crafting tons of eyes from it.
  The settlements with the maple source will help to level up Imbuing easy to 50 level

The skills which boosts your party mambers and gives the most of party slots

• 3 party slots
  
• Stat boosts
  
• Party relates modifications
  
• Party weight limit and inventory slot bonuses
  
  Skill gain exp rates
• Order 2
  
  Ways to gain the exp
  To train your first skill level you need your a party slot first. Obtain it from hunting or from 40 construction.
  The way to gain the exp is only one and annoying. Give your party members the orders. You will not take the exp from the order if previous order is not finished.
  

The skill which unlock the craft of the equipment from the fur and leather. Some of the material have a very specific bonuses, like stamina regeneration.

• Can craft a mask which negates daytime penalty for infravision
  
• Fur pounch to waist slot which can be handsome at early game
  
  Exp gain rates
• Craft: 1
  
• Salvage: 2
  
  Way to gain exp
  A lot of the leather can be obtained from the settlements, especially from your own one.
  Eventually a lot of leather and fur are gathered after cleaning points of interests.
  

Mace weapon skill which orientired on weapon piercing and stun

• Convert to true damage offensive modification for the skill. Just simple ignore any def. Extremely useful for getting 48 level of the skill
  
• Stun and damage bonus on stunned targets
  
• -25% enemy physical resist at 46 skill
  
  Exp gain rates
  Attack: 2
  Ability: 2
  
  Ways to gain exp
  The best way is a same as for the other melee weapon skills. Attack the enemies which cannot kill you.

The skill related to polearms

• +10% Agi stat bonus at 27 skill
  
• +25% crit damage at 18 skill
  
• Have more passive bonuses than other skills
  
• Agi and dodge makes your weapon grind harder.
  
• Additional range to aweapon ability modification at 15 skill
  
  Exp rates
• Attack: 1
  
• Ability: 2
  
  Ways to gain exp
  Same as other weapon skills. Attack enemy with melee weapon

The skill that related to she shields

• More defensive abilities, same as a passive ones
  
• ability to see behind you up to 33% at 46 skill
  
• Thorns at missing hp at 42 skill
  
• One more parry counter
  
  Exp gain rates
• Parry: 1
  
• Ability: 2
  
  Way to gain exp
  At the first, turn the animation speed in the options to the maximum.
  Then equip the shield and weapon with the most parry rate and stay under few of 1 damage dealing enemies. Regeneration and healing abilities would be helpful there. Don't ger overcrowded because parry count is limited to 1 by default
  Shield with the best parry rate: medusa shield.
  But you can take any shield with 50% parry rate with dao sword which have 40% parry rate.
  At other hand you can just use the block ability with cooldown reduction but this way is a lot slower than a blocking grind.
  As practice shows, this skill improves slowly as you grind your weapon skills by parrying the enemies

The fire related attack spells with high damage.

• Gives 100% immunity to ice later on
  
  Exp rates
• Ability: 2
  
  Skill gain
  Use the skill with the smallest cooldown. You can target the the destructable tilles with your spells as well.
  
  Beware! There is no way to get first exp! If you not choose the 5 level bonus for this skill at beginning or get the cheat/mod - the skill wil be locked forever

Weapon skill that related to the swords.

• Great parry rate
  
• Bleed related things
  
• Additional equipment slot for weapon
  
• Honorable execution at 50 skill, which is great to finish off the enemies.
  
• Chain attack modification for spells at 9 skill. Works great with a single target spells but can damage your team membets
  
• Ignore dodge utility
  
  Exp rates
• Attack: 1
  
• Ability: 2
  
  Way to gain exp
  Similiar to other weapons. The best with improving defence, because swords have a highest parry rate.

The skill that unlocks the craft of the clothes.

• The backpack and cargo pants will increase inventory slots and weight capacity for you and your party members.
  
• Easy to level up
  
  Exp rates
• Craft: 1
  
• Salvage: 2
  
  Ways to gain exp
  Tailoring skill grinds together with agriculture. You will get a lot of hay by the farming wheat in grass biome. Using magic ingredients is nesessary.
  

The weapon skill which related to knives and robbery.

• Gives great escape ability early on
  
• Unlock thief related actions
  
• +0.1% chance to critical hit per each point of Dexterity at 27 skill
  
  Exp gain rate
• Attack:1
  
• Pickpocket: 5
  
• Rob: 10
  
• Ability: 2
  
  Exp gain way
  Same as other weapon skills: by attacking the enemies with knife.
  

The skill that unlocks the craft of various weapons

• Craft: 1
  
• Salvage: 2
  
  Ways to grind the skill
  The first level is gained by salvaging. Attack easy points of interests with monsters with wears bone weapons.
  After that the best material to improve that skill is the bones. Craft bone knives until you unlock the bone spears, and then craft them until you unlock the wooden mallets.
  There are a lot of reciepes that uses the wood and they are preferable than the ones which uses the metal only.
  Wooden malled uses 2 planks and 1 metals, that makes it incredibly cheap to craft.

Skill gain rate data is taken from soulash\data\mods\core_2\skills.json
Why guide is vile because the powergaming can ruin the fun of the discovery for the newbies.
I will add a bit more info lately. Feedback is welcome