Read both short pieces related to the serve and the correct grip. One is informative and explains pronation. The wrist snap, to be done effective, must be done with the continental grip, with a wee bit more pressure with your forefinger and thumb on the grip. The forefinger and thumb are right next to each other. You have a little bit of looseness in your wrist, which you'll also have when volleying and hitting overheads.
These are all strokes performed with the same continental grip you use for your serve. Your forefinger is extended up the grip just as you do with your eastern forehand grip. Look above, 'Bevel 1 One' is where you place your palm for the continental grip(hammer grip) if your a right handed player. See the circled area, this is where you rotate up or down for the grip change. Palm on the 'right side' or 'left side' for your ground strokes(handshake grip). A Handshake has a bit more pressure in the palm than the fingertips. I've joke about it before with the team, wherein nobody, say a potential employer, likes a 'deadfish' handshake. REMEMBER a firm handshake, not a death grip. Don't forget to look he or she in the eyes.
The other is a simple activity to practice the service movement. You need not practice it with 'tight' clothing on, as you'll read in the piece. However please do it in front of a mirror. I was working with a few of you on this today. This is important to practice the weight shift in relation to the entire service movement.
