The sort of stretches done are similar to those done after the warm-up. Apart from aerobic and muscular work there are two more types of training that you need to do to improve your tennis skills. Speed work is necessary, especially over short distances like 5 to 10 metres. Practice sprinting as fast as you can over these distances, then stop, rest for 10 to 15 seconds, and then do it again. Try to complete at least 10 of these and work on going really fast.
Speed is the goal here.
The other training is Agility training. Use movement drills around the court. Set out cones and run around them. Work on changing direction side to side, and backwards and forwards as fast as you can. Use patterns that are similar to the way you move in a game of tennis.