Play your own game
Prepare as you usually do before playing a round.
This is not the time to invent new warm-up routines or new game plans.
Have realistic expectations. Or even better: Don't have any expectations.
Be target oriented. Use whatever works right there, right now. (as opposed to technique oriented)
And perhaps one of the few things you really can control: Be focused and concentrated and positive on EVERY shot. If you do that, you can be proud of yourself afterwords regardless of the result.