The first moments on board your cruise ship are filled with standard procedures, safety demonstrations and best of all, a champagne toast! If you've booked an all-inclusive vacation, once you board the ship, your wallet can go in the safe and stay there; all meals, drinks (including top-shelf tequila, scotch, and vodka), and gratuities are included.
And don't forget to bring your passport. Once you board the ship, the crew will stow it at the front desk. They're smart like that: Having guests tote passports on and off the ship is a recipe for disaster, so the cruise lines take care of immigration for all guests, pre-clearing you before you dock. You typically just have to show the customs officials, who hang out around the duty-free zone, your room key card to prove that you're a cruise passenger.
For when you do get off the ship, be sure to bring along an extra tote bag for souvenirs! You'll find everything from sunglasses to designer watches in port—all at tax-free prices.