One of the most overlooked parts of a well-rounded game is the second serve. Your first serves aren't always going to stay in, so you'll need a reliable second serve as well. But that doesn't mean simply getting it in play -- aggressive returners will feast on weak second serves.

The kick serve is one of the smartest second serves to hit. It is a safe shot, going high over the net and spinning back down into the service box, which reduces the chance of a double fault. And if struck correctly, the ball will kick up high on your opponent, making his or her return more difficult to hit. But it takes plenty of practice to develop a good kick serve. Teaching pro Katrina Adams shows you how it's done: