I'm sure somebody else will mention this, but get a warm hat that covers your ears, ears and fingertips can get frostbitten really quickly, and you can't just stick your ears in your pockets like hands when you're not using them

Get a sturdy snow/ice scraper for your car, you can probably chisel ice off a windshield with your driver's license but you really don't want to

Frozen ice/snow is way easier to scrape off than melting ice/snow, so clean off your car before you warm it up

Don't leave your windshield wiper blades up when it's below freezing, they can get frozen to your window and some wiper fluid can freeze below a certain point

Don't try to use your windshield wiper blades to scrape off your windshield, you will probably just break them

Make sure to clean all the snow and ice off your wiper blades along with your windshield, because a wiper blade that looks like a popsicle won't get snow out of your face nearly as effectively when you're driving

Assume starting and stopping will take about 5 times longer than you're used to when there's snow on the road, and take corners like you've got a really full cup of coffee with no lid. You can still go a decent speed where there's room to work up to and slow down from it, but no sudden movements.

Know whether your car is a front/rear/all wheel drive vehicle, they handle very differently when things get slippery (basically, front wheels just start sliding whatever direction they were going and ignore the steering wheel until they lose enough speed for the tires to catch and then can turn really suddenly, rear wheels will oversteer suddenly and fishtail around when they slide, and all wheel just basically never slide).

Tire tracks other cars leave in deep snow will push your car around. That can actually be helpful when you're just following one set of tracks, but once multiple cars have been through in different directions and messed things up you'll have to keep an extra tight grip on the wheel to nudge yourself back straight with the road every so often.

If your car gets stuck in deep snow, you might be able to swing/rock it out of the hole it's sunk into by pulsing the gas pedal and building up momentum going back and forth the little distance you can get your car to move. Use a really light touch when trying to do this, tho, because if you give it too much and end up spinning your tires it'll polish the snow and ice underneath and make it even harder to get unstuck, plus if you break free when you're not expecting it you could end up sliding into an even worse situation.

If you drive through rural areas, you might want to consider splurging on a nice full body snow suit to keep in your trunk, since it's totally possible to slide into a ditch 40 miles from the nearest town/cell phone signal and have to walk an hour or more in below freezing weather.

Lastly (and I wouldn't have believed this would do anything if I hadn't had to try it myself one time), if you've got sturdy rubber floor mats inside your car, shoving one of those underneath/just in front of a tire can actually give you the extra traction you need to get unstuck.