Tennis ball dribbling drills are great for improving your handles as well as improving your hand eye coordination. In a basketball game you need to be able to dribble the basketball from hand to hand without having to think about it. You also need to be able to dribble with your eyes up so you can see the floor, using the tennis ball will force you to keep your eyes up.
This basketball drills like this will help you to be able to learn how to control your dribble, keep your eyes up, and work on a specific dribble move to use in a game. Don't be afraid to mess up and lose your dribble while doing this drill, that is how you will get better.