The field of tennis psychology is not just common advice and tactical or mental tips. It is based on general and sports psychology and then applied to tennis specifically.
There are many common elements in the psychology of tennis which can be found in other sports too. An athlete that wants to perform at his peak needs to learn:
1. How to refocus
Many players start the match with good concentration but they drop their level of concentration because of disturbing outside events, pressure situations, emotional reactions to various events and so on. A player needs to learn how to quickly and effectively refocus to be able to play his best tennis.
2. How to control his arousal