How do you stop over rotating the ball when you shoot?

It's hard to say since we cant see your shot. Try standing by a wall and shoot the ball with one hand and see how much backspin you have then. Do you have someone that can watch what you are doing as you shoot? That might help you... IF you are in a school you can ask the coach..... or if you know a coach.... ask him if he can help you.

Take a look at this video, that boy is 14 and has a pretty good stroke.... he has been working on that for 4 years.

http://www.youtube.com/watch?v=SfTxHGOQdEc&list=PLCE640F251A4CDE74&index=1