Most players know that the toss is the most important part of the serve. They understand that a smooth, consistent motion using your shoulder turn, legs, and arm together will give you the best result with the least amount of effort. However, knowing these things and getting them to happen in a match are two different issues. When you are playing a match, the focus tends to go more towards the result rather than the process.
If you do not get your serve in, you do not get to play the point. If you do not hit your serve well, you will be in trouble quite often on the next shot. These are the main things that interfere with our ability to execute a good toss and a smooth motion. Try developing a routine with the physical part of the serve, as well as the thought process you go through just prior to starting the motion. Bounce the ball, point your racquet towards the target and start the motion.
Everyone is different so there is not one key thought that will be best for all players. Dividing the box into three specific targets to hit the ball to is a great way to keep your focus simple-out wide, down the "T" or right at the opponent (middle of the service box). I would recommend that most players use the middle of the box as the target at least 50% of the time. Pick a specific spot on the court and see how close you can come to that spot. This will keep your mind from wandering and focusing too much on the technique ideas during the actual point. It should keep you relaxed and help you gain confidence, therefore smoothing out the motion and helping you get that consistent toss you are looking for.
Remind yourself of the basic technique ideas in between points but stick with the routine and target idea once you are about to hit the serve.
Steve Annacone, USPTA Elite Pro, is the Director of Annacone Tennis (http://www.annaconetennis.com). For details on lessons and camps at Sag Harbor Park Tennis and throughout the Hamptons this summer contact email@example.com or firstname.lastname@example.org