All good points. To add to this, my first two tries were substantially less smooth than the third one. Third try was 50 points higher than the first two! Preparation was very different the last time.
For me, the sleep and food factors made a big difference. Consider keeping your schedule light and condusive to rest in the preceeding week. Eat well for that whole week. Exercise enough to keep you calm during the week.
On the day of the test, I treated myself to nicer (but not too much) than usual breakfast. Took a nice walk to calm myself. Stretched out to get the last bit of tension out of my body. Then I rocked it!