It's a good idea to establish a regular routine before pitching in a game. Get the advice of a pitching coach and follow it before pitching.
Pitchers on the local Koufax team start with this warmup sequence:
Run, stretch, throw,
then warmup pitching in the bullpen with a catcher
and work on the game plan
Go over signals and figure out which pitches are working that day
Make sure that the next pitcher in the rotation has time to warm up an inning before they go into the game.