Let's go look at the bike. Is it in top condition. I don't want to have to do bike maintenance on the side of the road in sub-freezing temperatures, so I do a thorough check to make sure everything works perfectly. I also tend to go with wider tires to avoid flats. I'd rather work a little harder riding than to change a flat in the cold.
Fenders are worth their weight in gold in New England.
I wouldn't think of doing a winter ride without them. And as usual, I carry enough tools to do minor roadside repairs, tire levers, tubes, wrenches, chain tool, etc. Since I tend to ride my commute bike all winter, I always have lights on my bike. The days are much shorter, and a flat, mechanical problem or long break can result in a ride finishing after dark. I tend to do smaller loops close to home, in case I need to bail out for some reason, like a blizzard, or a mechanical failure.