Consult maps and call ahead to your destination for road conditions. Be sure to have handy the list of road-condition hotlines and even program them in your cell phone if you have one.
If your car starts to skid, The National Safety Council and INDOT say:
Take your foot off the accelerator
Steer in the direction you want the front wheels to go. If your rear wheels are sliding left, steer left. If they're sliding right, steer right
If your rear wheels start sliding the other way as you recover, ease the steering wheel toward that side. You might have to steer left and right a few times to get your vehicle completely under control
If you have standard brakes, pump them gently.
If you have anti-lock brakes (ABS), do not pump the brakes. Apply steady pressure to the brakes. You will feel the brakes pulse — this is normal
Take your foot off the gas and shift to neutral, but don't try to steer immediately
As the wheels skid sideways, they will slow the vehicle and traction will return
As it does, steer in the direction you want to go. Then put the transmission in "drive" or release the clutch, and accelerate gently
Do not spin your wheels. This will only dig you in deeper
Turn your wheels from side to side a few times to push snow out of the way
Use a light touch on the gas to ease your car out
Use a shovel to clear snow away from the wheels and the underside of the car
Pour sand, kitty litter, gravel or salt in the path of the wheels, to help get traction
Try rocking the vehicle. (Check your owner's manual first — it can damage the transmission on some vehicles.) Shift from forward to reverse, and back again. Each time you're in gear, give a light touch on the gas until the vehicle gets going
If you are in an accident or run off the road, do not leave your car unless you know exactly where you are, how far it is to possible help, and are certain you will improve your situation.
If you are sure the car's exhaust pipe is not blocked, run the engine and heater for about 10 minutes every hour or so depending upon the amount of gas in the tank.