Originally Posted by Headshotterer
Toss the ball higher, further into the court. Snap your wrist and hit through the ball real well, and keep your eyes on the ball until after you make contact.
Now THIS is a great tip. It's hard enough to get people to do this on the forehand. But doing this on the serve, tho difficult, is game changing. Keeping your head down on EVERY stroke is important. Hits clean. I can really put a jolt into the ball, serve or forehand, and have confidence that it will drop in without me looking! As Fed does, KEEP THAT HEAD STILL.