How Long and How Often Should I Practice

For how long and how often should I practice. I've heard that I should practice at least 4 hours a day but I'm not sure.

What level do you play at? What are your goals / aspirations? Have you played before and at what level?>

i'm going into high school next year, i started playing about 4 years ago and my goals are improving on my jumping, one-on-one, and defense

My first suggestion is for you to go to the camps at the high school you are going to attend.... you will get a pretty good idea as to what they want you to work on.

The game is all about quickness... make sure you work on that ... if you look on the left side here... there are a lot of player tips and development drills.
Defense is all about heart and a desire to shut down the man you are guarding... OR being ready to help a teammate IF he gets beat. (Help D)
Rebounding... all about hard work and good positioning... kind of knowing where the shots are going... IF you do a search on line you will come up with some statistics regarding where most of the shots go.
Shooting is all about repitition..... you can never shoot too much... get a partner, makes it more fun and easier... you will get more shots in less time that way.

I hope some of this helps... IF not, ask any specific question and we will try to help you.

thank you, i'll try my best

Good luck and I hope things work out for you. The Bulls could use a center! :-)