Here's something I learned the hard way. Look at the receipts before you sign them. Getting off the ship at Nassau, we bought water. I saw the sign that said water was $1.71 and (would have sworn it said) w/lanyard $3.00. When I looked at my account later, I saw that each water cost me $4.71 AND the guy wrote himself a 15% tip!! So it cost me about $16 for three small bottles of Evian.
Yeah if you buy any drinks for the waiters (which includes the bottled water and the lanyards) then they do charge 15% grat automatically so don't be surprised by this
Also room service menu is in a book in your room but there are things that you can order free that aren't in the book such as Crustable Peanut Butter and Jelly Sandwiches, Grilled Cheese Sandwiches and Mickey Ice Cream bars
Look out for 2 for 1 drink offers (ask at the bars in the morning as sometimes drinks of the day are 2 for 1 first thing).
If you are buying clothes in the shops (other than on Castaway) you can take them back while on board if they don't fit so try them on before you leave the boat. On Castaway try them on before you get back on the boat.
Take twice as much camera film as you think you'll need (or twice as much digital memory) as you are sure to need it.
Snacks at 11.30pm are available in Beat Street/Route 66 and outside the Promanade Lounge if you are peckish at night (people never seem to notice this in the navigator)
Foreward elevators are always less busy than the central elevator and aft elevator. Central elevator especially in the evening is always busy! The kids clubs are around this area along with easy access to the Shops, Theatre, Lumiere's and Goofy Pool so most people end up in this elevator. Aft elevators are also used for Animator Palate and Parrott Cay and the drinks station and Mickey pool so again fairly busy. The foreward elevators tend to be for adult activities so not as many people using them except at show time as these are for the Quiet cove pool, gym, Walt Disney theatre, Beat Street/Route 66
Oh and an important one, if you don't like the food on one of the main dinner menus (i.e. the show dinners on your navigator at the 3 signature resturants) but you like something on one of the other main dinner menus you can ask for that. This is because with the rotational dinning when 1 of the 3 resturants has its show dinner/main dinner menu then the other 2 are having theres. With the special menus such as the Golden Mickey's menu or the Pirate Night menu then all the resturants have the same menu and so obviously you can only order off this. On my last cruise when we were dinning in Parrot Cay with their Island dinner menu (which is the standard Parrot Cay menu) I ordered off the Lumiere's show dinner menu because I didn't like anything in the resturant we were in and this was no problem.