Bullet stuffer is pretty well dead on.
I like the "military" style long johns that are waffle cut on the inside, from Cabelas. Over that would go a set of Thinsulate quilted thermals. Outer layer sort of depends on conditions. Filson Double Macinaw wool coat if little wind, as it quiets the whole mess immensly. If wind is a concern then an insulated wind stopping outer layer.
Wool socks, Smartwool to be specific, I dont worry about the liners as they are superfliouss with the Smartwool. Normal cold weather hunting >15 degrees will find me with a pair of 400gr thinsulate boots on my feet. I own a pair of 800gr boots that will rarely see duty unless <15 degrees or ice fishing all day.
Nothing beats a good wool stocking cap/ balaclava under a hood... if you are content to look out a pipe all day. I try to get by without a hood with a fur bomber hat, or in combination with a balaclava. Hands are my problem, and it all boils down to sweating. I do as well with a pair of wool liner gloves, and stick my hands in my pockets as anything. Wool chopper mitts with a BIG body warmer size chemical heater pad in each one is about as good as it gets.
Now take as much of the above as possible and put it in a big pack. I'm talking the thermals, the outer wind break the wool socks all of it. Get your butt moving and walk to your stand. when you get there you will most likely be sweating a bit, excellent. Unload that pack and get dressed at or near your stand. I try to find a nice log to sit on for this chore. I change out of cotton socks (stow in a qt Ziplock bag) into the wool, pull the thermals on put my bibs on add the coat and get on stand. No reason to carry the ruck to the stand unless it has your lunch or other stuff.
Finally I usually have something hot to drink in a 1 pint thermos, as well as some stuff to snack on. About the time I feel I have just got to get down and warm up I'll break into the thermos. Adding heat to the inside of the ol body helps me tremendously. They say caffeine will in the end make you colder as it dialates the cappilaries, cold fingers... I know. But that is what the heat packs are for.
Or scrap all that get yourself a pop up blind and a small propane heater

. Thousands of Finlanders here in Mn. can't be wrong