High weight squats like 3 sets of 6-8 reps. Wall sits while holding weight. If you have access to a plyobox jump over it continuously without stopping for as long as you can 3 sets a day. If you don't have a plyobox a chair will work fine just be careful. Squats are your best bet though.
Initially you have to start from the basic like running, it's help you to gain the stamina if you don't have stamina then i don't think so you can jump higher. Start Skipping it help you to jump consistency. Start do Athleticism. Sleep at-least 8 to 9 hours that help you to regain your energy.
A good way to start would be starting off on a trampling. Gets you practices how to jump, and just aim higher! Another thing would be your nutrition, I as a college athlete and advice to you would be having your 3 meals a day, and getting your 8 hours of sleep, which gets those extra inches of growth in you. Keep working hard, and I know you will make it! Good Luck!
Hi,
This is a good site where they teach how to jump higher http://www.goobypls.com/r/rd.asp?gid=492
Bye