1) Get a "ritual" - a process you go through before serving.
2) For your pre-service "pause", have your hands connected. Think Agassi, Djokovic, Sampras. Agassi and Djokovic have the ball in the center of the strings. Sampras had the ball in the throat (like normal people). Some people put their tossing hands together at the handle.
3) Don't move your back foot up. Your problem right now is you rotate into the shot before you actually initiate your swing. Why is this a problem? Consider moving your extended arm from behind you to your front as quickly as possible. Now, turn your shoulders to face the side, and do the exact same motion while rotating your shoulders forward. Which one has your hand moving faster? The method that incorporates the shoulder rotation. Which one also takes less effort to generate speed? The same method. When you pull your back foot up, your hips rotate forward, which draw your shoulders to rotate forward. This is fine if you load your shoulders against your hips (rotate it the other way) then release the load as you reach up for the ball, generating a fair amount of racket head speed. However, it requires more of a conscious effort to that than simply keeping the foot back and having the entire body rotate in a chain reaction to reaching up for the ball.
[K]Six.One Tour (3) 367.5 grams 31.7 cm balance.
Mains: Babolat/Wilson Natural Gut @ 49 lbs // Crosses: Luxilon Alu Power Rough @ 46 lbs