A good concept to think about, when playing tennis, is the correct use of spin. I hear and read about the "flattening" of the ball. Consequently, I see an entire generation of juniors trying to "flatten" the ball in order to try to win the point from all positions on the court. Looks great when it happens, problem is, it does not happen often enough.
You might hit a few great looking, low percentage shots, but it will not help you win the match. Concentrate on hitting every ball with some type of spin. It could be topspin or under spin. These spins allow a player to maintain good racket speed and control the shot. Quit trying to win the point every time you strike the ball. Instead, use your different spins to play much higher percentage tennis. Move the ball around the court until your opponent makes an unforced error or until they give you a ball which you can attack. The use of spin will help you become a better and higher percentage player.
Good luck on the courts!