OK-
start by writing what I didn't need last year.
Cake - I made 4 small ones and took two to my family. So I might make a couple of smaller ones and eat the iced/marzipanned one in December rather than Christmas.
No pudding- we don't eat them
Buy one packet of Sainsburys Taste the Difference Pies (but don't leave it too late like I did one year)
Wrap everything mid-December (I've bought boxes,bags,tissue and ribbon to make it easier. Stocking gifts though get over-wrapped to spin it out)
Plan days out in December (I've booked our Family Trip and Theatre + Tea for DD and I)
Go to London on a weekday to buy beer for DH
Do a Costco trip in November to stock up on binbags,dishwasher tablets
Avoid Lakeside/Bluewater like the Plague at weekends
Buy as much storable food (to put in garage and freezer) as possible. Bottles, tins, frozen early on.
Shopping trip for DH and I in November (Traditional for us. We do the last Friday in November and try to get as much as possible)
Lists Lists LISTS 
Get my hair cut and dye it in mid December
If anyone is ill, then hopefully (Cross Fingers) I'll be organised enough to cope.
Now that my DC are Secondary School age, we don't have as much going on at school, but DD does School Performances which was lovely last year.
Bought DS a Christmas Jumper already to save me searching every shop two days before the last school day (he told me on the Tuesday night he needed one for Friday. I only had the Wednesday available).
Got the DC Christmas Bedding, ready for the 1st.
Stock up on Paracetamol/Flu remedy/some bland easy meals/ice-cubes/nice bubble bath for me 
Make sure we have a full tank of fuel, screenwash, de-icer, salt for the path
Make sure everyone has gloves,waterproofs, proper winter shoes
Oyster Cards topped up in case I can't drive
Get some films for in betweeny days
Don't bother with the Sales. Too much aggro and really, there aren't the bargains anyway,