Be Social, (but not too social)

It's sometimes hard to imagine before you start drinking, but, the office party is actually intended for you to socialize. Don't kill the opportunity by talking and talking and talking about work. Pick a neutral conversation starter, like commenting on the excellent food and wine pairings, and go from there.
 
On the flip side, realize that you are still kind of working, so some subjects should be avoided. For example, no one wants to hear about your last visit to the doctor that ended in a colonoscopy. These are your co-workers, and unlike random acquaintances at a bar, you'll have to see them over and over again.