Rick Macci has some quick tips for adding power to your game. His three keys to generating power are:
Your shoulders need to work in tandem, going back as one.
Put all your weight on the outside leg: Power starts from the ground up.
Push off your leg as you rotate out to the target simultaneously, uncoiling all your power into the shot.
Macci, the founder of the Rick Macci Tennis Academy, has worked with a slew of former No. 1s including Serena and Venus Williams, Maria Sharapova and Andy Roddick.