A week tomorrow and we'll be checking in for our first ever Disney Cruise

What documentation do I need to keep with me when checking in? I've read the cruise website and its all a bit daunting. I've done my ESTA and have my passport. I've just printed off the check in form from the cruise website.

Is there anything else that i'm going to need to have with me?

This is really aimed at people in the UK who have done the cruise before.