I have a whole list of hacks I use/bring on cruises. My best one is to bring a night light. The your whole stateroom and bathroom is completely dark at night and the bathroom light is either off or fully, bright on..no in between. If you plug a small night light in the bathroom receptacle for shavers, it easily cures stubbed toes. The ONLY caveat is that you have to get one with NON polarized plugs. Polarized do not fit.
Among other hacks, we bring clothes pins to keep the curtains honest...we like to sleep in, past sunrise and don't like the sun peaking in through the cracks in between curtains. Magnets on the outsides of the curtains will keep them up against the wall as well (as someone mentioned that the walls are metal...they are). A hanging shoe rack, you know those cheap plastic ones you can hang on a door? Put that on your bathroom door and it will add a ton of storage for a lot of little things. Baby power, when sprinkled on wet, sandy feet will dry the moisture and the sand comes right off.
I'll post a few more when I check my list.