Keeping the ball low on your serves and returns is a technique that requires a lot of practice, and even after you think you've nailed it, in many instances the ball falls short of the net by a hair, yes, very frustrating! Learning and mastering this technique will give you a significant advantage over your opponent, the key, in addition to the low serves and return is the speed of the ball, hard and in play, which makes learning the shot more difficult, but with practice, you got this, and a significant advantage.