I really want to improve my game- I think that I have lost my shooting touch!

And what do you guys do to improve your defence and ballhandling skills?? I don't do jack all to improve my dribbling...except for dribbling and throwing the ball and catching the ball whenever I feel like it!

And can anyone tell me if my vertical jump is crap?? I'm 5'6" and I jumped 57 cms today...is that good or bad...(note: not to be racist but I am asian....we don't jump or run or do any sports!
