Backswing
Beginning players can simplify the backswing by taking the racket straight back below the waist before bringing it straight forward to hit, similar to a door opening and closing. Very quickly, however, you’ll develop your own unique backswing style. As long as you stay within some general guidelines, it’s okay to develop your own style of backswing.
The first rule is to start getting the racket ready (and turning your shoulders) as soon as you know where the ball is going. Don’t wait for the bounce on your side. The second rule is to find a backswing position that is neither too short nor too long. If you are a beginner, start by taking the racket back far enough to point it toward the back fence or wall. More experienced players may take the racket back farther in certain situations. If your backswing is short, you can’t hit with as much power. If your backswing is too long, however, the margin of error increases. Besides, you don’t always have time for a long backswing. The last rule is to develop an abbreviated looping motion with your racket—up, back, and then a slight hesitation before swinging forward to hit the ball.
Tennis: Steps to Success Jim Brown,Camille Soulier