After a bunch of winters riding a fixed wheel in the Northern MN winter, here are my observations:
1. If someone tells you to ditch your front brake in the winter because "It makes you crash", they either don't live within riding distance of a hill or have never really ridden in the winter on a properly set up bike.
2. Running slicks in the winter can be fun, but stopping and falling in traffic is not.
3. Studded tires - try them at least once (if you live in a snowy/icy area) on a properly set up bike (i.e. front brake and decent gear ratio).
4. So now that you tried #3 and have purchased studded tires, don't go bust out a 300' sparking skid down a dry road. It is bad your tires... but does look cool.
5. You will go down eventually, wear a lid.
6. It gets dark early, use proper lights.*
7. Know/learn how to change/patch a tube in the cold. Getting a flat shouldn't be an issue, even in the winter.
8. Play around with layering until you have it down to a science. Being cold sucks, but being cold and drenched in sweat is worse.
9. Many types of hiking boots are plenty warm/waterproof and will fit in large clips/straps.
10. Studded tires can be slick on dry pavement or brick, keep that in mind.
11. Grease everything, including your nipples.
12. Don't like my advice? Have better? Post it here.
*Knog frogs are not lights