Here are some tips I would suggest:
1. FLUSH YOUR BRAKE FLUID! You definitely want fluid without moisture in there.
2. If you haven't packed your front wheel bearings in a while, now would be a good time to do it. This way you can inspect the bearings, rotors, pads, and hardware while you're at it.
3. Perform a "nut and bolt." Put a wrench on any important fastener you can reach and check for proper torque. On the track is a bad place to find a loose component. Inspect all radiator and brake hoses.
4. Make a checklist of tools, parts, lawn chairs, EZUps or anything else you don't want to forget to bring. My memory isn't usually all it should be on race day.
Since you've autocrossed before, you already know about the torque wrench, air gauge and pump/tank, food, lots of water or sports drinks, etc.
5. HAVE FUN!!