as soon as you get there, get yourself a non alcoholic beverage. If anyone offers you a drink, motion to it and say, "nah, I'm good" or "got it covered."
You post awesome sober, so I have no doubt you'll be good company at the party sober as well!
Good on you for thinking ahead so you have some strategies in your pocket.
If you can drive yourself, good, so if things feel too hairy you can get a headache/stomachache or whatever and drive yourself out of there. Chances are there are other non drinkers there as well, often we don't notice that there IS such a thing when we are drinking ourselves!