Be fashionably late
Don't be the first to arrive -- or the last. Arriving in the middle of dinner is rude, as is leaving too early. That said, don't plan other social engagements on the same evening.
Mingle with everyone
Don't head directly to the bar or buffet table as soon as you arrive. Mingle first.
Keep your right hand free to shake hands.
Be friendly with everyone's significant other. They'll remember your kindness and courtesy, and may prove influential in your future career pathAvoid shop talk
Get to know your colleagues on a personal level. Ask about their favorite sports or recent vacation destinations. Be a good listener.
However, the company office party may offer a chance to chat with the CEO or other senior managers you don't speak with often. Consider what you will say if the opportunity arises. It's important not to monopolize the higher ups' time: introduce yourself and mention that you're excited about certain projects in the new year.
