RE: Layering techniques to keep warm
NO COTTON near the skin...
As far as socks... I highly recomend the Smart Wool socks.. they are a bit pricey... but worth every penny. I can wear 1 pair w/ my uninsulated Alpha Burlys all the way down into the 40s.. then I break out my 800 gram Danner Pronghorns. And these will keep me warm well into the teens.
Most people try to keep their feet warm by wearing more socks.. this is a big no no... When the body core cools... it pulls blood from the extremities. So if you keep your head, neck, body warm.. then the feet and hands will also be warm. If you wear 2-3-4 pairs of socks.. you're taking up all the air space in your boots... no air to heat up.. equals cold feet.
When it gets really cold... another trick is to throw some heat packs on your back around your kidney area and chest area... Some people use those heat packs that are for sore backs ect.. haven't given that a try yet.. but I'm sure they work also.