Pack a single outfit for each day. This sounds like a no-brainer, but a lot of people try to pack extra-light. Once aboard the ship, people often find that laundry, much to their surprise, is not complimentary. In fact, it's quite expensive. Check with your cruise line about laundry. Just in case, though, bring enough to wear that you won't be stuck worrying about laundry all the time--or its potentially sizable price tag.
Pack like you're going to the beach. Most days, you'll probably be fine in shorts or swim trunks for the men, a bathing suit and a wrap-around for the women, a towel and sunglasses. Bring sunscreen. Planning for a cruise in the way you're planning for the beach can trim your baggage down quite a bit. Along those lines, bring your own toiletries; you never know what your room will have available, despite the brochures. Shampoo, soap, shaving cream and anything else you might need in the bathroom should be brought along, just in case. Just don't worry about the bathrobe--almost all cruises lend you one for free.
When packing for a cruise, leave empty space in your bags--perhaps as much as half, if possible. Why? Because a cruise involves lots of shopping. Shopping occurs both on board the ship as well as when visiting the cruise's various destinations. You'll want a place to put it all and will be none too pleased if all of your baggage space is taken up by what you brought with you. Limit yourself to two bags per person.
Unless you've booked yourself a place on an upscale Crystal Cruise, you'll probably find that even the most formal of cruise events won't be black tie. For women, what you might wear to a cocktail party or, for men, to the office--should work fine. In other words, don't feel the need to pack all of your formal gowns and tuxedos. One formal outfit will suit you fine.
