Most players and coaches are focused on the technical aspects of the serve.
Using the right grip, practicing the toss, trying to make a good backswing, etc.
All these things are very important, but just focusing on technical things is not enough to be successful in a tennis match. Knowing the weak points of your opponent's return is much more important.
I've listed 3 ways to use your serve as a weapon in a tennis match.
The most important tactical rule is to serve outside the "comfort-zone" of your opponent.
Serving inside the comfort-zone of your opponent means your opponent has no trouble with the return because the serve is easy. When you hit a serve outside the comfort-zone, the serve is difficult and you are likely to get an easy shot back.
1. DIRECTION OF THE SERVE
The direction of your serve is very important!
When you serve to the red mark, you're aiming exactly in the hitting zone of your opponent.
Your opponent has no problem reaching for the ball and can hit a good return.
When you aim for the green marks, it's more difficult for your opponent to hit a good return, and you are likely to have an easy second shot.
One green mark is a body shot, which gives your opponent a lack of space and will make it hard to hit a decent return.
The other green mark is a serve wide, your opponent has also a lack of space and is likely going to hit a weaker return.
2. HEIGHT OF THE CONTACT POINT OF THE RECEIVER
Another important point is the height of the contact point of the receiver.
With your serve, you can give your opponent a higher or a lower contact point. There are many players who have a fantastic return when they can hit the ball at waist height, but when they have to hit the return higher or lower, the quality of their return goes down. By using topspin, you can give your opponent a higher contact point. By using a slice serve, you can give your opponent a low contact point. A low contact point is also possible when you hit a good wide serve.
3. SPEED OF THE SERVE
Another important way to serve outside the comfort-zone of your opponent is to vary the speed. Most players think that a serve with maximum speed is always the key to success in tennis matches, but that's not always true.
Try to discover what speed your opponent prefers, in order to hit a good return.
When he prefers a lower speed, then try to serve with higher speed in order to get back a weaker return and vice versa.
It happens a lot that other players or coaches are telling you that the forehand return of your next opponent in the tournament is very good, and his backhand weaker. However, sometimes the forehand return is only good when he receives a serve with a high speed and will make more mistakes returning a serve with a lower speed.
When you keep in mind these 3 ways for serving outside the comfort-zone of your opponent, you will be more successful in tennis matches.
Good luck practicing your serve!