Winter conditions are with us for many months of the year in Norway, so we are kind of used to it....
Most items listed in the above posts are quite relevant, and sensible to have on-board.
Apart from the usual "recovery and survive kit", which is in the vehicle for this period, I also tend to keep a sleeping bag, even for short country road trips.
Then if you do get stuck, and no recovery options are available, you can keep much warmer staying in the vehicle inside a sleeping bag, rather than just wrap-around blankets.
Have the blankets as well if you can......
And always keep the fuel tank topped-up as much as possible.
You never know when you will need that extras fuel, just to keep you warm and alive.
Use it sensibly - don't run it all the time - then you will have many more hours option still available - top up the heat, then switch off.
As well as a snow shovel, its a good idea to also have a good saw.
You can then cut wood / branches to help you get traction, or build a fire in severe cases.
(have a storm lighter in your survival kit)
Also useful if a tree has fallen over the track - you can cut off a few branches to make your way through - heavy snow can bend and bring down small / thin trees over roads in our area.
The photo below is the standard look for the car every day for many months over here in Norway.
Sometimes you have to clean the car in the morning for school run / work, and once again when you drive home later in the afternoon.
So we tend to always have snow brush with scrapers, de-icer spay, gloves, towel, etc..
.
We also change our tires for the season.
Virtually all of us over here in Norway have 2 sets of wheels for each vehicle.
One set has "Summer / normal" tires for general use (this rubber freezes solid in winter, and acts like a ice-hockey puck - not good for winter conditions)
The second set has "Winter / Studded" tires (softer rubber, different tread, and with metal studs if required).
Reducing air pressure to increase tread footprint can also really help at times and in emergencies...
If you are going onto a remote trail, provide a map and timelines to a friend, who will notify emergency services if you are overdue.
Good Luck.........
Winter is coming soon here !!!