Dress appropriately:

warm clothing
10"+ Gore-tex, insulated boots with lugged soles
long johns
ski gloves (and extras)

Bring:

shovel
recovery gear
sleeping bag(s)
jumper cables
extra rubber floor mats
kitty litter
come-along
air pump
extra cold weather gear
snow shoes
mobile phone
matches
newspapers
sidearm
knives

....

Airing down will be necessary in deep snow. Once the tires get even colder from the snow, the air pressure will decrease even more. It is important to have an air pump on hand to keep a minimum pressure in the tires and to air back up for road use.

Grip devices like old floor mats and kitty litter can be helpful, but plenty of shovel work may be required when you're stuck in the deep stuff.

Have fun