You'll want to pack clothing suitable for walking around all day. Think casual. T-shirts, shorts and jeans are all great ideas. But since it can get a little chilly at night or in the winter, it's a good idea to bring along a sweater or light hoodie. Florida is also known for a shower or two, so having a rain jacket with you is also a smart move.
Wear supportive footwear. Sandals and flip-flops might feel good for the hot Floridian weather, but you need to remember that you'll be walking around all day. Make sure you wear shoes with good arch supports and that your shoes are broken-in to prevent new-shoe blisters. A comfortable pair of sneakers is a good bet.
You can't take a trip to Walt Disney World without a camera. Make sure it works before you leave and pack extra batteries in case you're a shutterbug. There's plenty of places to buy batteries in the theme parks, but you'll pay a premium, so it's better that you bring some extra with you.
Since you'll be out of doors for so long, it is important to wear sunscreen and sunglasses to protect your eyes and exposed skin. Remember, even if it's cloudy outside, you can still be in danger from UV rays so lather up each morning, regardless of the weather.
It's a good idea to have water with you before you enter the park. If you're flying to Orlando, packing water is not practical, but you should get some before you go the park. It's important that you stay hydrated throughout the day.
If you're staying overnight at any of the hotels, or visiting the water park, you'll want to have your swimsuit handy or you'll be upset that you missed out on the water fun. You'll want to pack a pair of flip-flops or sandals for use in the water park.
You never know when it's going to rain in Florida, so pack your umbrellas to ward off any storms. People usually desert the parks when it rains, so if you have an umbrella and tough it out, you'll be rewarded with shorter wait times.
Disney World has some great "dress-up" restaurants in Epcot Center and in the Disney hotels. If you plan on visiting, you might want to wear something a little more formal than T-shirts and shorts.
