Third map or third set? If it's the set then:
- Making Friends: Using the well to turn a single coin into lots of piety and resetting using "Split the Pot" is by far the easiest way to summon your first fairies.
- Crumbling Corridors: You want to drag the altar close to the chest walls either on the top or bottom using a combination of spells, with "Binding Waltz" being the big gap-closer. Reveal any walls you want to break with care, especially at the start.
- Wicked Lighthouse: Summoning Plunder Hands is easier, but starting with Whispering Winds is also a viable strategy. Don't activate anomalies until you have to, you can use spatial rifts to move stuff out of the way. Pillars of eyes will sometimes let you get a full heal or allow you to hop over a wall. Don't overstay in the first map and try to bring full supplies into the second to focus down the chest.
- Astral Crypt: Any combination of gods should be viable. The solar route is more straightforward but the lunar route can allow you to get to the final room in better shape. Don't forget that land twister can move things over walls, that pillars of eyes reveal around your position, and that you can't use your current god's powers in the future rooms but can still gain piety.