It occured to me that much of a DM's time while world building is centered around the terrestrial, the ground around us, the ocean, mountains, forests, etc. However much of ancient culture was based around what was above them, the stars, the sun, the planets, and the like.
So it's something to think about with your world.
How many moons does it have?
How many suns?
How many planets can be observed?
What are the names of these bodies?