All professional athletes stick to a routine, whether pre-game, during the game or post game. Sticking to a routine breeds consistency and allows the athelete to control their game. Evolving a routine that works for you is an essential tennis tactic. Observe tennis champion Maria Sharapova and you will notice her routines.
In particular, she has a routine she follows in between games. After each game and before sitting down she follows the exact same steps, helping her to maintain her consistency and keep control no matter what is happening on the tennis court. Whether she is in front or not, she follows this routine and it is clear it is an essential tactic in her tennis game.
After the last point of the game she walks to the service box corner, steps inside the box and then makes a forty five degree turn to her chair. If the previous last shot has taken her out of court she will walk back in to go through her routine. Every single great tennis player also follows some sort of routine before serving. They may bounce the ball on the ground, adjust the balls in their pocket a la Agassi or fiddle with their racquet. Whatever, these rituals enable the player to focus and to maintain their consistency and control. Emulate these tennis tactics of the great players and you, too, can be in control out there on the tennis court.