What most pros say, atleast from what I've seen, is that they do the same thing warming up for every event. Just do what you always do for every tournament because if you're playing in districts then I know you must have played in some tournaments already. They say keep your routine the same for every tournament because it helps to calm your nerves and it feels like you've done it many times before so it's nothing new.

Works for them, they're getting paid lol.

Good luck!