The secret for me was the phrase, "steer into your fall." If you feel like you are going to fall to the left, steer left. If you are falling right, steer right. You'll need to practice somewhere with NO TRAFFIC and preferably no people watching Once you figure out how to stay up, think about practicing turns. I remember having a hard time keeping my turns tight enough to get around street corners when I was first learning.

Grass is hard to ride on so I wouldn't recommend that but if it works, go for it.