Brakes
Have your brakes checked to ensure even braking as brakes that pull to one side may cause you to skid. As well, if while braking you notice unusual squealing or grinding, or the brake pedal is stiff or tight when depressed, mention this to your mechanic. Repairs may be needed to ensure optimum brake performance.
Heating and cooling system
Use anti-freeze that is the right coolant for your car's needs (refer to your owner's manual). For winter conditions, it should be good to about -40ºC. As well, make sure your radiator, belts, and hoses don't have cracks or leaks, and that the heater and defroster are working properly. While it may seem odd to worry about your cooling system in the cold weather, your car can easily overheat in the winter. Plus, your cooling system impacts your heating system, so if it breaks down you'll have no heat inside the car!
Battery
Your battery can leave you in the cold, so have it checked. Cold weather is hard on batteries and starting your vehicle in cold weather requires a fully charged battery. Be sure connections are clean and tight and there is no corrosion. Consider replacing batteries that are several years old.
Exhaust system
Check the muffler and tail pipe system for carbon monoxide leaks into your vehicle. Leaks into the vehicle shouldn't happen regardless of season, however, it is particularly important in the winter when the windows of a car are usually closed.
Heaters, defrosters and wipers
You should always ensure your windshield can give you clear vision of the road and traffic around you. Have your car's heaters, defrosters and windshield wipers checked to make sure they are fully operational. Install new winter wiper blades and use cold weather washer fluid (one that is rated to -40ºC should do the trick). Make sure you have enough washer fluid too because on messy, snowy days you can easily go through a couple of litres.
Lights
Check to make sure your all your lights are working, front and back, and make sure your headlights are aimed properly. During the harsh weather conditions you can find in the winter, like blizzards, storms and freezing rain, you'll be happy that you can see and others can see you on the road.
Oil and filters
Dirty oil can give you trouble in the winter, so change the oil and filter before the cold weather sets in. Other filters need attention too - fuel, air and transmission for example. When getting your oil changed, check out your owner's manual to see if it suggests you change the oil with one that is rated for the cold weather.
Tires
Check your tires monthly for wear-and-tear and proper pressure in the
cold weather. Without proper maintenance, your tires could cause you to
lose traction and control of your vehicle in the winter. As the weather
gets colder, tire pressure decreases, so make sure your tires are
properly inflated to the levels recommended in your owner's manual.
Also, check your tires to make sure they're not worn, bare or damaged.
If you install snow tires, you'll improve your traction and your
vehicle's handling through the ice, slush and snow. Install four,
identical tires so that your are not mixing tires of different tread,
size or construction.