Here's what I learned from my second race:

1. Do it again! It is as fun as you remember, possibly even more fun. And you'll be able to start covering over the memories of how badly you did in your first race.

2. Lower your tire pressure. I'm a roadie by nature, and as such in my first race I made the total newbie mistake of running my tires at max pressure (65 psi). Then I came to these boards and read a few threads and found out everyone else is running as low as they can get away with. My tires (Maxxis Locust CX) are labeled with a minimum psi of 50, but I ran them at 45 psi on a soft course with no problems. I probably could have gone lower. Somewhere I read that 25% of your body weight is a good starting point.

3. Mud holes and water features have a curved bottom. If you have to run across a mud hole, two steps, one on each side, might be better than one step in the middle. In my second race, there was a deep mud hole. Sometimes when I went through I sank in up to my knee. Sometimes I only sank in half way up my shins. Thinking about it later I realized in was because I was hitting the center of the creek bed on the deep sinks.

4. Use higher gears. My first race I started in the granny gear and stayed there. In my second race I resolved that I wasn't going to do that, so I started out in my middle chainring and stayed there. Starting out required more effort, but overall it wasn't that much harder.

5. Warm up. This is probably a no brainer for most people, but I didn't do it in my first race. I didn't hurt myself or anything, but I wasn't loose. For my second race, I got there an hour and a half early and had time to preride the course at a slow pace a couple of times, practice some sprint starts to see what the traction would be like and do some stretching. By race time, I felt ready.

6. The guy ahead of you is as tired as you are. This really surprised me. Finally getting the chance to pass a few guys, I was surprised to see that consistently, after I'd spent half a lap right behind these guys, as soon as I passed them they fell way back. The only thing I can figure is that they were pressing to stay ahead of me, and then when I passed them they eased up a bit. This was very good because I was afraid passing them would be wasted effort and they'd just pass me back after the next turn. Not so.