If you want to get through Etrian Odyssey III’s Yggdrasil Labyrinth you have to make good maps. This video should get newcomers to the series up to speed on mapmaking, it’s actually better than the in-game tutorial.
Making loops is a really handy trick. After you create a loop you can hit play and wait for monsters to come to you. That’s what how I’ve been leveling up in Etrian Odyssey III.