bring cash!!!!!!!!!!!! and if you think you have enough, bring more!!!!!!! just don't forget it when you leave the ship, or make sure you bring plenty when you leave the ship. (well at least in nassau anyway).
but you will want it for tipping, especially room service.
i might be in the minority here, but the over the door shoe thing and lots of other stuff, i wouldn't worry about. we had 3 in our room, and we had plenty of room for everything. this was on the dream, so not sure about the other ships.
and don't forget your key card placed into the slot (inside your door) turns the light and tv on! just remember that you placed your key card into that slot, don't think you lost it already.
bring a light sweater or jacket thingie to dinners, especially if you are prone to getting cold. you don't want to be sporting a tablecloth at dinner! :lookaroun