For general catering over Christmas I make lots of things in advance and freeze them, e.g. soup, quiche, nice breads, braised red cabbage etc. All these things can then be defrosted and heated up when you need them.
Generally for Christmas Eve I would have something like a home made quiche with salads and maybe cheese, sage and onion bread (quiche and bread taken from freezer), then a trifle for dessert.
Christmas Day I do the roast dinner (we usually have chicken as we prefer it) but don't bother with a starter as there is so much of everything else. So it would be roast chicken with stuffing, bacon rolls, chipolatas, bread sauce, roast potatoes, roast parsnips, brussels sprouts and gravy. Then Christmas pud and brandy sauce.
I make the stuffing, do the breadcrumbs for the sauce, prepare the bacon rolls, prepare the sprouts and peel and parboil the parsnips the night before. Definitely agree with making a list of timings in advance, so you know when everything needs to be done.
We don't bother with tea much on Christmas Day, I just get out some cheese and biscuits and Christmas cake.
On Boxing Day I would usually do soup and a nice bread for lunch, and in the evening do cold chicken and ham with braised red cabbage and baked potatoes, chutneys etc. Soup, bread and red cabbage can come from freezer, so there's not much cooking to do. Then left over Christmas pudding or mince pies for dessert, or last year I made some yummy ice cream in advance, which I could get out of the freezer when required.
I also make sausage rolls in advance and put in the freezer, so they can be used whenever you need them.
In terms of shopping, I usually order my chicken, ham, bacon, chipolatas etc from the butcher and collect on 23rd Dec. I also do all my fruit/veg shopping on 23rd at the greengrocer. Much less hassle than fighting your way round the supermarket. For general groceries I order an internet supermarket delivery to arrive a few days before Christmas, so I'm not having trolley wars (it's usually hell in supermarkets just before Christmas).