I have a dressage show tomorrow, any tips?

I'm 27 and have been riding english since I was 4. I actually have only ever shown hunter and my last show was when I was 17. So it's been 10 years. Tomorrow will be my first dressage show EVER! I'm competing in the 2011 USDF Intro tests A and C. I am confident about remembering the test and I just have to remember to focus on showing my horse and thinking one step ahead about what I'm doing and where I'm going. Riding her up and into the bit, maintaining bend, half halts into downward transitions, firm halt at X so she'll square up, balanced seat, etc. Since it's a small show tomorrow, tests are not split up into age groups. I'll be competing mostly all against kids. haha I'm also sharing the horse I'm riding with another kid at the barn I ride at. Ok so I know to smile when I ride in the test, as I salute, and also at the end. It can give the judge a good impression and help them remember you. What else can I do to be at my best? I don't know how good these kids are and I'm not worried about it, but I also want to do my best. Thanks:)