What has worked for me:
1) Food: just eat whatever you regularly eat before a normal workout (don't try and do anything special). The last thing you want is an upset stomach.
2) day before a race: 3-4 miles at warm-up pace + a couple of strides to feel good
3) race day:
5 hours out - last meal before race
4:30 hours out - 30 min nap
4 hours out - 10 min shake out. Then chill until coffee
2 hours out - start drinking coffee (if your stomach can handle it), otherwise run gum.
50 mins out - begin warming up (find a warm up routine that works for you, it doesn't have to be anything special. should include a 2-3 mile run, some stretching, drills, and strides). most important thing is that your muscles are warmed up and ready to go when the gun goes off.
That's my pre-race routine. Try it out and play around with it until it works for you. Not everybody's pre-race routine should be the same!
Hope that helps!