Eat well, sleep well, practice practice practice.
i can't say you'd be the next LBJ however never let down of your dreams!
I can't promise you that you'll become as good as LeBron James but if you want to become a good basketball player you need to practice, and practice the right way.
Find a local program or a local coach and let them teach you the correct forms and the correct techniques of basketball and then dedicate yourself to practicing and perfecting. It will take lots of time and dedication to the game, at times it wont be "fun" but you will improve. Push yourself daily to do each technique perfectly.
Study the game, watch basketball at all levels and become a smart player, watch what players do right, watch what they do wrong. Learn from other players so that you can adapt your game to make the right decisions.
Take care of your body. Eat right, drink water (cut out the Soda), exercise every day and push yourself.