A couple quick thoughts...
As the season wears on, good food sources close to bedding is key.
The rut is winding down, so deer now are more apt to bed close to food, in heavy cover, and only get up to feed, then go back to the bedding. Deer often bed very close to the food source in late season, so you have to be careful to slip into the staging area between the bedding and the food, without bumping the deer from the bedding. Be extra mindful of the wind and the bedding area.
I've also found that it's a good plan to stay out of my property for about 10 days after rifle season ends, to give the deer time to settle down.
Another thing is, if it's really cold, deer are more apt to feed in the late afternoon and remain bedded in the coldest AM hours. If the late season weather is nice, in the 40's and warmer, deer may well feed more in the AM.
Also, the woods are now wide open and unless you have great background cover, you're more apt to get busted. A ground hunting situation in thick pines/conifers is something you should consider.
Other suggestions are, make sure you use unlined wool, since about everything else is noisy in the often dead calm late season woods. Fleece is quiet, but not very warm. All other materials make noise in the cold.
Practice with the heavy gear on and wear a wrist guard. Bulking coats make for string slaps.
Consider shooting a lower weight bow. That 50lbs may feel like 60lbs after 2 hours in the bitter cold.
Be extra quiet getting to your stand. While many drive a truck or ATV close by in October, December deer may be far more spooky with that noise. Try to slip in with extra, extra quiet caution.
A couple other observations are, if windy on a cold late season day, deer don't move. I recall a study where if the late season wind was like 15-20mph, deer movement basically stopped.
Stay off field edges and instead think staging areas.
Deer will often feed just before a snowstorm, when the barometer is falling. (Seems fishing can also be good right before a storm also).
If you hunt a treestand, use either an open camo pattern like ASAT/Predator/Vertigo or (secret tip) use your camo blaze orange from gun season. Not solid orange, but camo'd orange. To a deer looking up, camo blaze orange looks like the winter gray sky with branches or leaves, depending on the camo pattern. Two of my best treestand bucks were in bitter cold weather, wearing blaze camo coveralls. I never once had a deer remotely notice me. It's a far better pattern than any "blobbing" Real Tree or Mossy Oak.
If you hunt in a treestand or ladder, re-check every strap. Every creaking noise is worse in the cold.
Once your feet get cold on late season sits, your hunt is about over. I've tried all the tricks and after owning a sporting goods store, tried most well known boots.
While I'm not a big Cabela's fan, they do sell the best pac boot for sitting...
http://www.cabelas.com/mens-insulated-hunting-boots-cabelas-predator-extreme-pac-boots-150-brown-mossy-oak-break-infinity.shtml?WT.tsrc=CSE&WT.mc_id=GoogleProductAds&WT.z_mc_id1=03 223101&rid=40&mr:trackingCode=0230FFB0-5EA4-E011-9A77-001B21631C34&mr:referralID=NA&mr:adType=pla&mr:ad=21046044551&mr:keyword=&mr:match=&mr:filter=43600703111 Another trick if one has sweaty feet...
http://shop.dsehealth.com/categories/Certain-Dri-Feet/