Hi Debbie!
That's my favorite time of year to visit. The parks and resorts are absolutely beautiful when they are decorated for Christmas.
My advice is to slow down and enjoy the special holiday offerings. Don't run through the parks from one attraction to another. Instead, slow down and enjoy the details and the decorations. Do those things that are only offered during the holidays; any attractions you miss will most likely still be there on your next visit.
Mickey's Very Merry Christmas Party in the Magic Kingdom is a "must do". It's a hard ticketed event, meaning you'll need a special ticket for it, but it's worth every penny. It has a special parade, special fireworks, special shows, free cookies (well, they're included in the price of your ticket), and snow on Main Street!
In Epcot, the
Candlelight Processional is spectacular. It should not be missed. Since it is very popular, I recommend that you consider purchasing the Candlelight Processional Dinner Package. I also enjoy visiting the various countries in World Showcase and listening to the various stories presented as part of Holidays Around the World. I think learning a little bit about the culture and customs of the various countries is what World Showcase is all about.
Also be sure to visit the various resorts. The Grand Floridian and the Wilderness Lodge are spectacular. The life size gingerbread house in the Grand Floridian has to be seen to be fully appreciated. If you're staying in an Epcot resort, head over to the Beach Club and Boardwalk to see their fantastic Christmas decorations.
Enjoy planning and write back if you have any more questions!