I love doing courses and I usually go over the course 5 times before I ride it.Also if you suddenly forget your course during your ride then try to find the best line to another jump I had to do that once and it worked out fine for me.
At shows, I try to get my course as soon as I can to begin looking it over. If you are allowed a walk through, I definitely recommend doing it! It'll help you have a feel for the placement of all the jumps in the arena before hand. I find it especially helpful to close my eyes and envision myself riding my course, step by step.
Remember to go in with confidence!
Good Luck :)