-Pack half as many clothes as you think you'll need.
-Rolls clothes, they'll fit better and have less wrinkles.
-Pack plastic grocery bags. They'll come in handy for packing dirty clothes to return home, or for wet things, etc.
-Whether you're doing Disney's ME or not, be sure you have everything you need in your carry on that you will have with you at all times. Your luggage could get lost, or your ME delivery to your room could be VERY late (as ours was, late as in way after ds's bedtime and we had no jammies for him).
-We normally always have leftovers if my dh, myself and both kids each order a meal. When away on vacation, we generally will split 2 adult meals, or dh and I will split and adult meal and each kid will get their own and we'll help finish theirs if we're still hungry. No point in ordering more food than you really need as it's just a waste when you can't bring it back home.
-A large breakfast, snack and then a nice dinner usually suffices for us. 3 'squares' a day is too much food for us when we're on vacation and doing alot of running around/touring.
-If you're taking small children; consider a 'Tink' or 'Mickey' (or whomever) daily gift. Bring small dollar store items, leave them for Mousekeeping when you leave the room. They'll place them with the towel animal on the nice clean bed. The kids will learn to be excited to return to the room to see what Tink or Mickey left them. After the first day, you can use this as a way to stop the 'gimmes' in the gift shops! (i.e. Johnny, we can't get something now, what if that's what Mickey already left you in your room? Don't you want to see what Mickey might have left you?) Oh, and Tink gifts can be left near the window with 'fairy dust' (a little glitter) nearby.