Most of the the important stuff has already been covered.

For me the most important thing has been getting to know how my body responds. When you're really at the limit is when the mistakes happen. With all the things in a race that require your attention it's easy to get distracted. Check in with yourself regularly and gauge how you're feeling and adjust your effort accordingly.

The best piece of cross advice I've ever gotten is to start on the outside. The center of the pack is where all the congestion happens.

Hammer on the bumpy stuff. It is no less painful if you take it slower. These are great places to make passes.

Don't sweat your barrier technique too much. Your dismounts and remounts will improve with practice. It *is* important, but in reality the barriers are a small part of the race. The most important part is setting your bike down smoothly.

Learn how to shoulder a bike the correct way and only do it when absolutely necessary.