Boots. I (metaphorically) kick myself when I just throw on my sneakers and end up in foot-high snow.
If there’s snow on your gloves or toque, put 'em on the heat register. If you do that after morning recess, they’ll be dry and warm for lunchtime recess! Never hurt a heating system I know of.
Your aim is to only forget to unplug the block heater cord once during the winter. But remember to plug it in every night or you’ll be sorry!
Make lots of suppers where you put stuff on the stove. Nothing like warming your hands over a pot of boiling perogies!
If you have a truck, you need to put weight in the back. Do not pass go, do not collect $200 until you have done so. When old farmers who grew up doing stupid stunts with farm trucks swear by this, you must abide by it.
Carry sidewalk salt in your trunk! Along with a shovel! We had to dig ourselves out of the parking lot at work a couple of weeks ago, I was one of the only people with a shovel in my car.
Second the layers - socks, longjohns, pair of pants, t-shirt, sweater, parka, gloves, long scarf (suitable for wrapping up your face if it gets too cold), good winter boots, and a headband are my usual cold-weather gear (and by cold weather, I mean
-20 to -40ºC) for going out walking.
If you’re going out in fairly cold temps, if you just jog a little bit at the start of your walk, you’ll warm up even faster. I’m always warm by about 15 minutes in regardless. I wear a headband instead of a toque so I don’t overheat, actually.
Get outside as the temperatures start to do down - I’m a firm believer that you have to be outside and moving around to get used to the temperatures. If all you ever do is go from heated house to heated garage to heated garage, you’ll never adapt.
Never hurt a heating system I know of.