Rule 1 - Don't talk about work. This is a social occasion with your colleagues, not a strategy meeting. Don't be a bore. For one evening, people want to forget about budgets, sagging revenues and redundancies.
Rule 2 - Don't boast about your bonus prospects. There will be staff there who will get little or nothing this year-end, and hearing what you expect to receive will quite likely want to punch you!
Rule 3 - Don't ask for a raise. Just because the boss is smiling for the first time since the last Christmas party doesn't mean this is a good time to point out your increased salary expectations.
Rule 4 - Don't take a souvenir from the restaurant / hotel / bar or whatever. Cutlery, table decorations, napkins – they don't belong to you. Remember - bankers always get caught!
Rule 5 - Don't reciprocate advances from married colleagues. It will end badly.
Rule 6 - Don't at any point display your exotic (or erotic) dancing skills.
Rule 7 - Keep cool - a lot of skin is not appropriate at a work function. And being sick on the dancefloor isn't usually a career-enhancing move.