Christmas dinner rather than Christmas lunch sounds good. We always invite DFil round because we lost DMil a few years ago and family is very inportant to him. BUT it also means single Bil and Sil come too (they all live together) and while they are nice people they are conversation vaccums, don't help, don't play with DS, don't thank us for the food/wine. Ideally I'd like DH's other siblings to offer to host, then we can stay at home, not going to happen
However, a Christmas dinner would mean more of the day for DS to ennoy presents, more time relaxing in pyjamas and not running around cooking so early.
Make my Christmas cards in November (I only do around 10) so they're ready to go to family abroad on Dec 1.
I put away DS' stocking tat when the decs were packed away so he'll see them again Christmas day: slinky, whoopee cushion, a drinking straw that winds around your head and looks like glasses, some Smurf finger puppets. He had a lot of fun with them, but they were ignored once The Presents were unwrapped, so he can see them again every year until he's 18 
DH was in charge of Christmas breakfast this year whuch worked out great - pancakes! With rainbow sprinkles! And cinammon sugar mmmmmmm.
Make sure if one day over the hols is busy, then the day before and after are chill out days, i don't want to pack it in.
Take more photis and go for long walks on the beach - make festive crap with driftwood!
I have already started sewing for this Christmas
