In keeping with the water bottle theme of the original question, If you are going to a warm part of the world I would suggest bringing your own insulated water bottle like a Hydroflask and using ice to keep your water cold. The Vero bottles are not insulated and your water will get warm during the day (even with ice in warm places). On our WC I bought an insulated bottle in one of our early ports and left my Vero bottle in the room.
Other things that we found helpful are magnetic hooks (and maybe some binder clips) that you can use on the metallic walls to hang things and organize pieces of paper or to hang hats. My wife also brought a shoe organizer that hung from our closet rod.