Most people focus on what clothes they need to take on their cruise. If a fancy one with dress codes there is lottos angst about the right mix of gowns, suits and more casual clothes. If a mixture of weather then layering dominates the packing. But you should spend as much time thinking about non-clothing items to bring. Here are some things I recommend
Here are a few helpful items to take:
Electrical plug adaptors. Cruise ships usually mostly have American two-pin plug sockets, using 110-120 volts and so bring adaptors as needed if from other countries.
Extension cord. Many cabins have limited number of plugs and so an extension cord enables charging and use of multiple items at one time.
Chargers for your electrical items like mobile phone, laptop and tablet.
Earplugs and eyeshades are often useful.
Personalised First aid kit. Bring remedies for you usually use for ailments such as seasickness, headaches and diarrhoea, along with a pack of plasters.
Guide books and maps if you are planning to self-tour in some ports.
Entertainment (e.g. iPod, Tablet, eBook reader, or books).
Small backpack to use when on excursions, to carry your camera, identification, water, and something warm, if needed.
Magnets. Many cruisers use these to pin daily programs and other materials on the walls, which are all metal.