WHAT TO WEAR - WINTER EDITION
Avoid thick, heavy layers, try multiple thin layers instead for ease of movement and adjustability (remove or add throughout the hike/run)
Cotton is not your friend, it doesn't stay warm once damp; focus on natural wool fibers or polyester
Sweat management is a very real problem, once you get damp it's hard to stay warm, dress so that you're a little chilly in the beginning and you'll warm up once you move
Carry extra layers for longer hikes/runs, these can be useful to add if you get chilled or change out your layers if they get damp/sweaty
Wear a headlamp for those dark early morning and evening excursions
Reusable or single use hand/toe warmers can be a great addition, and can be used in a pinch on any body part that's getting chilled; keep a few extra in your pack for emergencies
FOR YOUR HEAD
Change your headgear based on temperature; for warmer winter days try a buff (a tubular piece of cloth) or headband over your ears, pull out that trusty toque for colder days
Consider wearing a buff, or very thin scarf, over your face and nose for extra cold days - protect that nose
FOR YOUR UPPER BODY
Leave the bulky ski jacket/long jacket at home - they'll limit your mobility
Try adding a variety of layers with a thin(ish) wind resistant jacket over top, or a thinner "puffy" style jacket for the brutally cold days
FOR YOUR HANDS
Try out different thicknesses of gloves and see what works best for you; most times you may not need really thick "ski mittens" for most days
Try layering thin gloves under mittens for extra warmth
For long hikes/runs you may want to consider carrying an extra pair of gloves in case one pair soaks through (hands get sweaty and snowy)
FOR YOUR LEGS
Much like your upper body, layers are key, try layering long underwear underneath of running tights or hiking pants and/or shorts/skirt over top of the pants
Bulky snow pants can make movement challenging and get sweaty fast; if you're still cold with layering you can try thin, insulated hiking pants or nordic ski pants
FOR YOUR FEET
Traction is key; use microspikes (tringular spiked ones, not small, round traction devices) with your trail runners/hiking boots, or use winter running shoes (i.e. icebugs) with built in spikes
Ensure your trail runners are gortex or duct tape the mesh areas of regular trail runners
Avoid large, heavy snow boots; they make technical steps challenging
Don't be scared to experiment with layers you already have at home and try out different combinations, you'll quickly learn what works for you!