Tips/HOw to win an equtation medal? Horseback riding?

i am qualified to a medal and i realllllly want to win. i just need a few tips or what the judges are looking for on how to win. i have an appendix quarter horse. some tips on keeping heels down in a show environment when everything else is running in ur head? shoulders back? anything else? mainly over the jump because that is my problem. my horse is sometimes spooky. any tips for that?: because its pretty random....thanksss i have until September until the final medal and i take 2 lessons a wk. 1 private 1 group and free ride 2 times a wk.