Check the literature you receive at the gate for special services you might need and locations of restrooms, lockers, show times, stroller or wheelchair rentals, etc. Be prepared to put down a deposit for rentals and have coins for locker rentals. These provide a great place to store jackets and packages. (Yes, you will probably need a jacket after dark.)
Don't try to pack too much into too little time. Try to spread your Disneyland experience over two or three days. Schedule breaks at the hotel for naps. Decide what you most want to see and get there early. Remember, children, the elderly and the disabled get particularly tired. Take advantage of early morning entrance that comes with your package deals and use this time to go to the more popular rides that have long waits later in the day.
Leave your car at the hotel and take advantage of the shuttles. They are wonderful for saving time, money and the frustration.
Most of all, remember you are on your vacation. Take your time and make the most of it, and remember to have fun.
