One of the big things that separates pros from amateurs is practice. When a professional steps on the practice court they have a plan — amateurs / weekend warriors / club-level players / etc. don’t.
An amateur’s practice session consists of hitting some forehands and backhands, some serves, and perhaps some point play. It’s relatively unfocused — it’s generic.
A pro, however, practices with a purpose. They not only work on technique, but also tactics. Often, their practice sessions are tailored to their next opponent. By putting a little though into how they practice, they get more out of their time on the court.