The weeks of Thanksgiving and Christmas as well as the week after Christmas are some of the busiest of the year at Walt Disney World. The parks are in full holiday mode, all is merry and bright, and thus quite crowded. It's fun to be there but you need to be prepared.
Plan, Plan, Plan
The best thing you can do is plan! If you want to visit the parks over the holidays, make sure you book early. The Disney resorts do book up so if you want to stay on property booking a year or more in advance is a good idea. I recommend staying on property due to some of the perks, I'll talk more about this later. Besides room reservations, dining reservations are imperative. During normal season it's important to make dining reservations early if you are looking for table service experiences, busy season makes this all the more important. If you typically just eat whatever quick service food is around you, I would recommend reconsidering if you are traveling during the busiest times. It's a nice break from the crowds to be able to sit down at a table and relax for an hour. These dining reservations should be booked 180 days in advance for best availability and times.
Set Your Expectations
Be ready for the crowds. Everything will take a little longer; the bus line, getting into the park, and making your way to the attractions. Because of this I would select five attractions that are your priorities, three of them being what you FastPass. Your goal is to ride those and everything else is gravy so to speak. Things that can be easier to see are the shows at the various parks and some of these are high on my "must do" lists (e.g. Finding Nemo the Musical and Frozen Sing-a-Long).
Get There Early
During the holidays the parks can close due to capacity. Magic Kingdom typically closes first because it's the most popular and because of the park's smaller size. This means getting to the park when it opens is important. Otherwise you may show up and be turned away, and having to change the park you are going to. I mentioned earlier that I recommend staying on property because of the perks. There are lots of perk to staying on property and they are outlined in this article. What is not mentioned is that when the parks close due to capacity, they do it in phases. Guests staying on property will have priority over guests staying off property. And Extra Magic Hours, available only to resort guests, definitely make a difference over the holidays!
Make sure you plan early if you want to visit over the holidays. Know that you will be contending with large crowds, so prioritize what you want to see and do and show up early. The parks are extra magical around the holidays and if you are prepared, visiting at this time can bring a little extra joy to your holidays.