Originally posted by WuffWabbit:

The best way to level is to stand on a ground chunk that is the level you want, then spin in a circle leveling as far around you as you can. You level based on the chunk you yourself are currently standing on.

It still leaves some potholes though. OP, I'd recommend grabbing your cultivator and put grass everywhere so the potholes aren't as noticeable. Otherwise, you're going to drive yourself mad constantly getting stone and going step by step trying to even everything out perfectly.