Tennis has become so physical that going out there and just being able to hit the ball nicely is no longer enough. You have to be able to cover the whole court and change direction within a couple of milliseconds. Your hand-eye coordination has to be very good otherwise you won’t be able to handle the speed of the serve or the groundstrokes of your opponent. Therefore, it is important to be ready when you step onto the court.
Whenever I am at home playing or teaching in a club I notice that most of the players don’t take themselves seriously enough. Tennis is an individual sport and you are responsible for yourself. There is no substitute for your position as there is in team sports. There is no tie. There are a winner and a loser.
Having said that, doing some extra things will allow you to get the maximum out of your game. Warm-ups and cool-downs are very important. They help you create routines and send out signals to your body; hopefully, the right signals. Taking an extra 15 minutes before and after a practice session will help you to be more successful on the long term. No matter which level of tennis you are playing, it will have an impact on your game.