Have fun. Don't drink so much you get sick or black out. If you're going with a long-time partner, you know the drill. If you're going with a DATE, don't be a pushy asshole. And again, have fun!
My prom itself was mostly boring, but we had a limo for 4 couples (customary in NY/NJ in the late 80s) and went to NYC after. We had a lot of fun there and all made it home safe. The one of us (not me) that brought a date (not a girlfriend) had a miserable time because the girl was being, shall we say, "charitable," by going with him, and we wound up dropping her at home early so everyone else could just have a good time.