I don't cook a traditional Christmas dinner, but I'm in the US so I do cook Thanksgiving dinner which is pretty similar to Christmas dinner. I don't always make the exact same recipes. There are some staples, but I like to mix in a few new things (like different vegetables) every year. What I do is sit down with all the recipes and read through them. Often a recipe will state that it can be made up to two days in advance (for example), kept in the fridge and then reheated. Or some parts of recipes can be made in advance and finished nearer the time. Anything that can be done ahead of time I do. I use all this information to make a schedule of what to do when.
So, for example:
Sunday - make cranberry chutney
Monday - toast the bread for the stuffing
Tuesday - bake a pie
Wednesday - make the artichoke dip (for a nibble earlier in the day).
I also do a pretty detailed schedule for the day itself, including things that can be done earlier in the day - prep veggies, etc. And then work backwards from when I want to serve the meal, including things such as changing the oven temperature, taking dishes in and out, and even laying the table and getting out serving dishes.
I enjoy this process and I enjoy creating a feast for my loved ones, but I do also like to have time to relax on the day itself and planning carefully like this enables me to do so.