Many players learn to put decent spin on their serves. However, they often find it difficult to disguise that spin. Why not develop a no-spin serve, with a fast, violent serve motion? Change directions as the racket contacts the ball (contacting the ball as the racket is changing directions at the split second where it is nearly motionless), or contact the ball near the handle of the blade (where the racket is moving slowest) so there will be little spin . . . and your opponent will be left making a snap decision on what spin is on the ball. Very often they will react to it as if it has spin. For example, if they think it has backspin (but doesn't), they might open their racket to push, and pop it up. Or if they attack it, they'll lift it off the end. A no-spin serve is just as effective as a spin serve if the opponent thinks there is spin on the serve!