For the run: Don't get sucked into the pace at the beginning. You want to go out a little hot, but don't follow the morons who go batshit crazy at the start. About 1200m into it the vast majority of them WILL shit the bed. Run your first 400m a little more briskly than your planned place, and then settle into the groove. Then when you are about 1000-800m from the finish, slowly start to notch it up by looking ahead and picking people off. Work from one runner to the next, just like a race.
Concentrate on keeping your head up---look ahead, not down. And keep those arms moving!
I second the pre-race dump.
I had a buddy who used to down a few scoops of NO-XPLODE before races. His hands would twitch when he'd get on the line. I wouldn't advise that though...