1) always keep the car in gear, no power to wheels = no tracton.
2) if your car starts to drift while keeping a continuous speed, downshift and if you dont regain traction lightly brake
3) keep the revs low, on a DOHC motor max horsepower happens when the secondaries open up so keeping the revs below even 2500 is definitely a plus
4) think further ahead, double or even tripple your stopping distance, and if road conditions are really bad, downshift while slowing down.
I am a master at driving in the snow, its my favorite thing to do during the winter, I have it down to a science.
One and 2 go against EVERYTHING I learned at a performance winter driving school. For one, if you are in a slide with the fronts, it is GOOD to put the car in neutral, and the sooner the better. There is less resistance on the wheels, therefore they don't fight the snow/ice, they start rolling, giving you actual traction, and control of the car.
If the car is drifting (I assume you mean in a skid) downshifting is a bad idea for the same reason -- this is the same reason you don't brake during a fast turn -- you are loading the suspension and just begging the tires to break lose. One might be able to pull out of it, but I don't think I could. Again, neutral is the better policy.
Three and four, on the other hand, I agree with completely. The guys driving like idiots, and ignoring the conditions, are the ones that end up in the ditch...like I did.
Get snows -- if they save you once, they paid for themselves by making sure you didn't have to pay your insurance deductible.
If you normally follow by two car lengths, follow by more. Leave more space at stops (in case someone else didn't buy snows).
And take it easy -- getting somewhere an hour late is better than not getting there at all.
Lastly, in really bad weather, discretion is the better part of valour -- stay home.
More tips:
http://www.carsp.ca/winter2.htm