While you're on stage, it's important to keep things simple in your head. I love this quote from Keith Hill and Marianne Ploger at www.musicalratio.com:
...you must sing all the music in your imagination, as you play, with such intensity, conviction and energy that the little that "leaks" out into the music as it is heard will ravish the listener.
Then, all you have to do is breathe deep, blow fast, and enjoy making music!
Priorities in Performance
Recital vs. Road Race
A Perfect Performance is a Hole-in-One
What is Your Swing Thought?