Make sure you have antifreeze in your coolant and washer fluid, check you tire pressure and make sure to give it 4-5psi over normal since it will drop once you get onto colder conditions. Bring a shovel, road flares, extra cloths and gloves in case you get wet and make sure your cell is charged and have a charger in the car.
If you don't have all season tires and don't want to bother with buying AS tires or chains you should NOT drive that car to a place where you will encounter snow. If you do have a good set of AS tires you should still get a set of chains to meet requirements and in case you do need them.
As far as driving goes, here are some basic tips for winter driving:
1.SLOW DOWN! Don't try and out run the weather once it gets overhead, you will only put yourself and others at risk. And if you have an ego you should stow it in the back, don't be a ass when driving in snow.
2.No sudden turns or breaking. You only have so much traction and breaking can cut that by half, hitting the breaks and cranking the wheel will only result in a dramatic crash.
3.Give your self plenty of room. When flowing someone give your self a six second buffer, pick a point on the road (like a mile marker or a road sign) and start counting once the rear of the car passes it and stop when your front bumper crosses it. If it's less than 6 you are too close.
4.If you do find your self sliding DON'T PANIC, let off the gas, if you're getting sideways then turn the wheel (gently) into the slide, once you get going straight again start slowly applying the breaks (NEVER SLAM THEM, ABS is worth crap in the snow even with trac control) and cut your speed by half and continue on until you find a safe place to stop and figure out what your options are for getting home or to a safe place to wait for the roads to clear.
5.If you have to pass someone, give yourself three times as much time as you normally would when passing.
6.Don't drive if you know it's going to be bad out.