Refrain from any discussions concerning office problems. Be sensitive to the fact that such a party is a social event and not an occasion to spread gossip. Dress for the season, but in good taste. Daring and indiscreet fashions for men and women can create poor impressions that question your judgment. Don't monopolize a conversation or the time of your boss or other executives.
Discretion is the key word.
It's important for everyone to show they can relate under such circumstances. After all, your future career could hang in the balance.