Carly gave a great demonstration where she "dressed" herself in layers, gave us recommendations about how to stay warm and comfortable with layers.  Carly encourages thrifting and finding cheap ways to key pieces for winter riding.  I appreciated that she opened up the floor to the winter bikers in the room so we could share what works for us.  Read her recap below, and add your knowledge to the comments section.

FEET - Keeping you extremities warm is a big deal. Numb toes is common when cycling, even in summer, so your feet especially will need good insulation.
Socks - Thick wool or warm tech fibers are preferred.
Boots - Look for waterproof, insulated footwear. Most cyclist prefer wide, grippy soles if they're not clipped in. If they ride with cleats, they will use a winter pair, or at the very least cover their summer shoes with the neoprene booties.

HANDS- Windproofing, insulating & retaining function of your hands is important. Usually, basic mittens or gloves will do, but there are some special considerations.
Liners- Are useful for that extra warmth. You can also carry an extra pair if yours get wet.
Lobster Gloves- Are better than mittens when it comes to dexterity, but sacrifice some warmth. They also usually have reflective bits which are a plus when riding in traffic.
Handlebar Gauntlets - Use these when you're going for the EXTREME biker look.

HEAD- Keeping your head warm (but not too warm!), your face & eyes protected makes for an enjoyable winter riding season.
Helmet- It's far more likely that you'll crash in the winter. Be safe. Drooling is not cool.
Hat- You can easily regulate your body temperature by wearing different hats. Most cyclists prefer a warmish hat with a brim to protect eyes from the elements.
Mask/Balaclava/Gaiter- Keeping your neck, chin & cheeks warm, these pieces need to be flexible & multi-functional. You don't always need to cover your entire face, but sometimes you really do.
Eye protection- Sunglasses, bubble goggles, safety glasses. Keeps stuff out, keeps your eyes from watering uncontrollably.

THE REST OF YOU - It's a layering game. Some cyclists prefer tech garments, some prefer less specialized items. The main thing is to keep yourself warm & dry.
Baselayers are important - find out which you prefer: acrylic, silk or wool. Carrying extras is a good idea if you tend to get sweaty.
Rain/Windproof garments - These are great for keeping the precip out,  but have a well-deserved reputation for keeping your sweat in.
Inslulation- Use as much or as little as you care to. Remember, if you're comfortable in the first three blocks of your ride, you're overdressed & will regret it. You can always pedal faster to warm up, but it's not as easy to stop & shed layers.
Visibility- Being seen will keep you safe. Bright colors will draw attention to you. If you prefer somber tones, use ones with reflective details or add your own with iron-on reflective tape. Wear blinky lights on you as well as your bike.