This is something from mental coaching and improving your serve in learning and stressful (match-)situations.
From studies about „choking under pressure“ and from Yogi Berra (US baseball coach), we know, that „you can’t think and hit at the same time“. In stressful situations (serving in hard scores in tennis, putting in golf, shooting penalties,…) a lot of athlets start thinking
about failure and about their technique. This uses capacity of the prefrontal cortex and prevents the access to automated and frequently used motions.
The consequence is a slowdown of the motion and can lead to deviations from a successful solution.
In this situation we use so called mental tricks to „trick the mind“ and to avoid conscious thoughts. For your serve in tennis the following tricks can be helpful. When you think about supposed „best technique“, you have no access to motion transfers from already known motions (for example: „throwing and serving“. Just the same happens in developing and learning skills.
To „trick the mind“ in your serve you can use words with three syllables, like „Am-ster-dam“ oder the german word „E-del-weiss“. This corresponds to the tripartite rhythm of the tennis serve.
Thinking about Amsterdam or an Edelweiss and visualizing this calms down your prefrontal cortex and allows your brain the access to saved motions. To make this a firm part of your mental toughness, do it regularly in practice and in your matches, even in save situations.