how on earth do you navigate through the dungeons?

i beat skeletor and didn't even go that deep and I am getting cornered by those mages that throw things at you, mind you those things pierce through walls. how am I even supposed to dodge those things?

and if not that then a swarm of skeletons come in and overwhelm me. any tips on how to navigate through the dungeons? because I feel like at this rate, Ill reach the end game when i have kids and they grow up.