10 Tips for your Cruise 

1) U.S. citizens will need a passport for cruise travel. Visit: http://www.travel.state.gov/ for more info.
2) Pack a small 3 way plug so that you can plug in your cell phone, video camera, etc.
3) Look at off peak sailings which offer the deepest price cuts.
4) Ask your cruise specialist to seek out sailings that offer value adds.
5) Understand the features, benefits and limitations of group rates completely before you book.
6) Carefully check and replenish toiletries before departure using “travel sizes” when possible.
7) 7Flying to port of embarkation?  Leave a day earlier to avoid possible delays.
8) Leave photocopies of your passport at home with relatives or friends and carry another photocopy with you.
9) Most cruises are very casual these days, and call for “country club casual” wear.
10) Most first time cruisers opt for a week or less in order to "test drive" the product.

Source:
http://www.cruisejungle.com