The best tip I've seen on these boards came about 5 years ago and that is a clear over the door shoe organizer as mentioned above. I bought mine at Walmart for $6 and it's never missed a cruise. You can keep suntan lotion, MP3 player, sunglasses, flip-flops, ball caps, batteries, camera, loose change, highlighters, make-up, daily activitie sheets, etc. in them. This really helps keep the room clutter to a minimum.
Also, I wrap the handles of my luggage with alternating red and white electricians tape so it looks like a candy cane. Never a problem finding my luggage.
Don't forget bungee cords to keep those balcony doors open.