The absolute best thing I had with me on our cruise was an over-the-door shoe holder (clear plastic kind). I placed it on the bathroom door and kept all manner of things in it like: extra film, batteries, keys, sunglasses, medication, hand cream... everything. That way it wasn't piled on every spare surface in the cabin and I could always find what I needed. I'd never go on another cruise without one. Also, if you're in an inside cabin, do yourself a favor and bring a nightlight for the bathroom, cause the cabin is pitch black in the night when you have no window!