Here is how:
There are number of things you can do. Some of the best exercises that come to mind are:
crouch - stand. This one is very basic but effective exercise. What you do is simply get in a standing position, crouch down, and get up with your arms extended if front of you. Do that 50 times to complete a set and about 3 sets a day. Rest about 2 minutes between sets
jump rope - of course, I can't leave out this one. there is no need to explain jumping rope. I'll just add that you can try to switch legs when jumping. For example jump for 30 seconds with one leg then 30 secs with the other and then immediately go with both legs. And if this is too advanced for you, you can train with your own numbers of reps. Then as you get better gradually increase the numbers.
stand under the rim and try to touch the net (if you can) with your head. So that means that when you jump, you'll put down your arms and just go up with your head. Then, as soon as you touch the ground jump again. do this, ahemm, 10 times to complete a set and 3 sets a day would be enough.
there are so many exercises to put here that really work.