When the level finishes loading, you get to a screen, where you can already see the layout of the level, but need to click to actually start playing it. This is you opportunity to plan how you're gonna approach the level. Sure, if you're seeing it for the first time, you don't know what the goal is gonna be, but you can still look around and come up with a rough idea what to do first.
Since you don't start with any resources, there are always some "obstacles" than can be picked up/cleared without spending anything. Look how far do these items allow you to go, and decide which building you want to repair first (spoiler allert, a lot of the times it's gonna be a saw mill). Think about how much Divine Might you will have access to right away and how much you will need to get to the first Altar and use the extras to speed up getting there.
Also... don't give up when you don't get all 4 stars on the first try. Yes, sometimes, maybe even a lot of times you will, but other times, it might take several attempts. When you didn't complete the level in time, think through what slowed you down. What did you miss? Did you lose time because you didn't notice that hidden path until way too late in the level? Did you accidentally spend too much of something and had to wait for the resourses to refill? Maybe you banished the wrong creature at the wrong moment. Or maybe you're not aware of doing anything wrong. Either way, thinking about the experience you gained and revising your strategy will help you overcome the problems.
Remember, that the solution is always there - you just need to fully understand the level and it's mechanincs.

The most unpleasant aspect of upgrading buildings, at least for me, is the fact, the if the upgrade is still in progress when the timer for resource refill reaches the end of the cycle, you DON'T GET ANYTHING from that cycle (not even the amount of the previous production level). On the other hand, when the upgrade is finished before the end of the cycle, you get the upgraded amount of resources. This is a very important detail to keep track of when you're starting upgrades. Also, the upgrade timer starts when the character gets to the building, not when you click the upgrade button, so it's often useful to click the button immediately after the end of one production cycle (or even slightly before it, depending on the time it's gonna take for the character to get there).

The production boosts are an absolute necessity when you're playing on "True Expert" difficulty, but they must be used wisely. Getting the extra resources for a bit of Divine Might can be convenient in different phases of different levels - sometimes using it at the beginning will go a long way towards completing the level in time, other times you'll mostly be using it to get the resources to refill storages in the repairing levels.
Either way, keep in mind, that while Leada is most of the time the one to work with Divine Might, she doesn't boost buildings - Protus and Adoris do. This is especially useful when you're in a hurry and need to keep the Altar of Zeus active constantly, as she will be earnign back the Divine Might you're using up for boosting.
At first, I didn't realize that BOOSTING DIFFERENT BUILDINGS COSTS DIFFERENT AMOUNT of Divine Might. Another tricky aspect is, that just like with upgrading buildings, YOU DON'T GET your normal production amount of the resource if the boosting is still in progress when the timer for resource refill reaches the end of the cycle.

What I find trickiest about collecting the Golden Sheep is choosing the right time to start collecting them. In some levels, you can access the Altar of Afrodita early on, but you will just be wasting resources if the sheep spawn into an area you cannot access yet. Because of this, I tend focus on getting the sheep only after I've got access to most parts of the level if not all.

This very level was the first one to majorly stump me. It's rather confusing when you see it for the very first time and raising the sea floor ASAP feels important.

The problem with that is, that raising it once (which costs 7 Divine Might) isn't enough and you need to raise more parts of the sea floor for the first one to be of much use. My succesfull strategy was taking care of everything accessible right away first and only then proceed with raising the first part of sea floor.
The most important step at the begining is repairing the Saw Mill, which will leave you empty handed in terms of material for a bit but is absolutely necessary for succesfull completion. Even though having a significant amount of time when all you can do is wait for resources to replentish, is usually a bad sign in this game, spending too much Divine Might to speeding things up often backfires on you as well. The sweet spot in the first phase of this level are 2 speed ups - first one right away and second one after you upgrade the Saw Mill to produce 2 units at once. (see Phase 1)


Phase 1 - getting Saw Mill to level 3

• clear your way to the Saw Mill (+4 material, +1 gold, +2 marble, +7 DM)
  
• repair Saw Mill (-5 material)
  
• boost Saw Mill (-1 DM, +3 material)
  
• let Saw Mill finish 2 production cycles (+1 material per cycle)
  
• upgrade Saw Mill immediately after getting 5 material (-5 material)
  
• boost Saw Mill (-1 DM, + 6 material)
  
• upgrade Saw Mill again (-5 material)

Phase 2 - repairing Altar of Hermes

• continue clearing your path towards the Altar (-5 material for the first hole, +2 fish, + meat, + DM, + gold along the way)
  
• boost Saw Mill once more (-1 DM, +9 material)
  
• when you have one of the guys free, mine gold and marble 1x (-2 DM, +2 marble, +3 gold)
  
• repair the Altar of Hermes and boost it ASAP (-1 gold, -3 meat, + 3 DM)

Phase 3 - getting Sheep Farm to level 3

• if you followed both previous phases precisely, you should have 8 DM on hand right after the Hermes' Altar boost, so use them to remove the large boulder (-8 DM, +8 material)
  
• boost Altar of Hermes again (-1 gold, -3 meat, + 3 DM)
  
• repair Sheep Farm (-4 material, -4 DM)
  
• upgrade Sheep Farm 2x - with a bit of luck and the Hermes boost going on, it's very possible to do both upgrades within one production cycle AND still get the resource harvest of that very cycle (-10 material total)

Phase 4 - onwards to the Altar of Zeus

• boost Altar of Hermes again (-1 gold, -3 meat, + 3 DM)
  
• raise the 1st section of sea floor (-7 DM)
  
• defeat the crab (-5 meat, -3 DM)
  
• boost Altar of Hermes again (-1 gold, -3 meat, + 3 DM)
  
• boost Sheep Farm (+9 meat, -2 DM)
  
• trade meat to get fish (+5 fish, -5 meat)
  
• boost Altar of Hermes again (-1 gold, -3 meat, + 3 DM)
  
• defeat the octopus (-3 fish, -5 DM)
  
• boost Altar of Hermes again (-1 gold, -3 meat, + 3 DM)
  
• defeat the Cyclopes (-3 meat, -5 DM)
  
• boost Altar of Hermes again (-1 gold, -3 meat, + 3 DM)
  
• repair Altar of Zeus (-5 material, -5 marble)
  
• boost Altar of Zeus (-1 gold, -3 fish, +3 DM)

Phase 3 - onwards to the Altar of Afrodita

• raise the second sea floor (-10 DM)