The first thing you should do is get your car serviced and inspected well before the really cold temps arrive. You want to make sure all routine maintenance has been handled – and any repairs that may be needed are made.
A very common problem in cold temperatures is the painful discovery of a dead battery. In frigid temperatures, batteries lose power. It also takes more power to start your car in colder weather, so this is doubly important. Most auto parts shops will check your battery for free these days, so there’s no reason not to know you have a good battery going in to the winter months.
You should also fill your windshield wiper reservoir before bad weather hits. I’d recommend filling it regularly, because few things can make driving more difficult than a dirty windshield. If you buy the kind with anti-freeze in it, it can double as a defroster for those days you’re forced to park out in the snow or ice!