Probably the most important thing is DON'T BE LATE back to the ship. You are required to be on board 30 minutes before sailing. They WILL NOT WAIT for you if you are late. Keep your watch on "ship time", and not "local time" if there is a difference between the 2, which I don't think there is if I'm remembering correctly.
The only exception to waiting is if you are on an excursion that you booked through the cruise line that for whatever reason is late getting back to the ship.
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)