1. Get sleep beforehand. Really. Work on it for like a week leading up to it.
2. Avoid activities that are likely to irritate the joints. Even little things, like indulging your son's favorite game of going up and down stairs.
3. Do not overexert yourself the day before. No matter how much you think you can handle it.
4. Smile. It makes a difference.
5. Find the camera far in advance if it is lost.
6. Walk the course ahead of time if possible. Perfect sidewalks are nowhere close to uneven, convex streets.
7. Relax! Ask questions if you've got'em. If you don't know something, chances are good you're not the only one. Asking might help the volunteers coordinate.
8. Volunteer at a race sometime.
9. DO take the water with you.
10. Warm-up AND stretch before the race.
11. No matter what is going on, take time to cool down and stretch after the race.
12. Celebrate, regardless of outcome, because no matter what, you showed up! That's more than most people do.