A good drill is doing a cross-over into a between the legs,behind the back, then between the legs in one complete motion.
So you start dribbling with your right hand. then do a cross-over to you left hand. You then do dribble the bal through your legs, with immediatly after that a behind the back and then get the ball in front of you again.
This practices combinations of dribbling moves together. The faster this is done the better of a dribbler you are.
You can also wear gloves when doing this. This will make you "numb" to feeling the ball and make your hand remember how to dribble. It simulates you dribbling with your eyes closed.