Often it's best to avoid EMH. Go to a park the morning immediately after it's had Evening EMH.
Go early, be there before opening. Immediately get FPs for your #1 ride. Try to ride as much as you can as long as you can handle the crowds. Always get the next FP as soon as possible.
Leave once you can no longer stomach the crowds. Head back to your resort. Take it easy in the afternoon. Relax in the room or poolside, if it's warm enough. If you have the energy, visit other resorts to check out their Christmas decorations or stop by DTD.
Once you feel you've rested & reenergized, head back to the parks, the later the better. Avoid the first parades/shows. These are absolute mad houses. It's much better to try to ride attractions while everyone else is lining up for the parades. Stay as late as you can.
Repeat the cycle each day until completely exhausted. Then remind yourself never to go during Christmas week again.