At many tests I ran back in the day... They would ask people to sign up for running order to accommodate pros, etc. I enjoyed going very early and often first. Would evaluate the test by what my dog was doing in training, against what the test was set up to do. Watching other dogs is nice, but you do not know how they are trained and can begin to over think it.
If you have a chance try to go watch a Master test you are not running at and watch the mechanics. Then watch the dogs and see the variability of their reaction to the test.
The previous suggestions about airing your dog are great. If you can find some place, not on test grounds, to go do some simple marking drills and get your dog focused and settled into his/her job. I was so concerned about me being too hyped up at my first Master test, and thus the dog feeding off me, I forced myself to be very slow and deliberate about everything we did that morning, got a little carried away as she was a bit sluggish to start the test. But once the birds were down, she knew what to do.
Remember, we do this to have fun. So try to enjoy yourself.