I usually stay to the right as I normally would, except in conditions where it's nothing but icy ruts along the curb. As the winter progresses and more and more stuff gets pushed up along the side of the road by passing plows I find myself drifting further into the lane. I will take the lane if necessary but, for the most part, there is still room for me and passing motorists. In my experience many drivers give me more space in winter than in fair weather... I hope that remains the case. Make sure you're well lit because many drivers won't expect to see a bicycle being ridden in the winter.

So far I've never had to move for a plow, but I think I would dismount and get out of the way to allow him to pass.

I give myself extra time to get to my destinations - probably about 25% more time, although it likely only takes about 5 to 10% longer than normal. I am slowed marginally by my studs but the extra time is more due to riding more slowly (and more safely). You just never know what to expect so it's good to be proactive. Don't forget to budget extra time for getting dressed, undressed, etc.

Fenders are an absolute must (I'm assuming you already have them installed) and if you use panniers make sure they're waterproof, or better yet have a rain cover for those slushy, sloppy days because they will get coated with slop. I also use a dollar-store showercap to protect my saddle when parked outside; it helps keeps my butt clean and dry on the ride home, plus doubles as a helmet cover when necessary.