Make sure that you bring a couple of nice suits. They have a formal night where all the girls dress up in evening gowns and the guys wear nice suits.
Bring an extra bag for suveniers and a plastic one for wet clothing.
Figure on spending a grand or two on drinks and such and bring money for the casino if you like to play. they issue you a card that the people just swipe whenever you want drinks and such. Before you embark, you give them a credit card to use and they run it at the end. So, make sure that you have a card with a few tousand available to spend on it. I'm not sure what they do if you don't. (Maybe require a cash deposit, I guess).
If you get a room with an ocean view or with an ocean view and private veranda, make sure before you bood that the view is not blocked by a damned life boat...lol.
When you get to the port, let the porters take your luggage onto the boat.
When you disembark, it is a big cluster $^%#. Ignore where the directions tell you to go, and get as close to the exit as you can get about 10 minutes before they tell everyone to line up (They tell everyone to go to different meeting places first to explain disembarking, but DON'T GO) We didn't have a flight to catch, but lots of people who did had to carry all their luggage for over an hour in line because disembarking was going to take so long and they were worried about catching their flights. Instead, just let them take your luggage for you the night before and get down to the exit floor early.
The special drinks of the day are about $7.50, I think. If you want to get a girl drunk, buy her 1. I had one not knowing how much alcohol was in it, and I was stumbling drunk before the boat even left the dock.

I didn't even mean to get drunk.