Visualize the size of your cabin on your cruise ship. For individuals on a cruise ship the first time, the amount of space, or lack of it, can be surprising. The average cruise ship cabin is smaller then the average hotel room, and this results in a lack of storage space for luggage.
Choose long and thin luggage. It is possible to put your luggage under your bed on a cruise ship, but the space underneath the bed is limited as far as height goes. This means you will want to consider luggage that is longer and wider and rather shallow in depth. This can actually help you keep your clothes wrinkle-free as well, with less room in the suitcase for bunching.
Using regular luggage is possible if it's just one or two pieces, as these can fit in the bottom of your cabin's closet. Any other luggage that is standard size can become cumbersome in the room though, due to lack of storage space.
Use suit bags for your formal attire you want to bring on the cruise ship. This will allow it to lie flat. Also, the suit bags can hang in the closet for storage in the cruise ship cabin's closet.
Pack toiletries in a small bag or case that can serve to carry small souvenirs back from your vacation. You will have space in the case as you use your toiletries on your vacation and this will be one of the best spaces to pack the purchases you make at the various ports of call.