Pre-Performance Speach
Moments before I play I say to myself, "Relax… Play Musically… Play Repetitively."
"Relax" prompts me to take a couple of breaths... slowing down my breathing and my heart rate. I play better when I'm relaxed.
"Play Musically" prompts me to not try and impress anybody... letting the music flow through me... not forcing anything.
"Play Repetitively" reminds me to use Chorus Forms... phrasing known to be highly affective/memorable.
If you don't have a saying before you play, I recommend you work on one... it can be amended as you go... targeted to what you're working on at that time.