As others have mentioned, layers. It is a pain sometimes, but carry your outer layers to the stand, then take a moment to cool off from the walk in and then dress before climbing into your blind or stand. The few days we have had into the 30s this year I have worn a silk base layer with a mid weight merino wool layer. I have Gray Wolf Woolens Wolfskin that I wear over that until it gets single digits on 20s and windy, then the wool comes out. Depending on where I am hunting, I have carried my entire outer layer and walked to the stand in my longjohns with a pair of gym trunks over them to keep from overheating.
I use a fleece stocking hat until it gets really cold, then I sometimes put a wool stocking hat over that.Unless it is single digit temps, I don't even wear my hat when walking in. Face is easy as I wear a facemask or use a neck gaiter all the time and I have a full beard that helps too.
For my hands, I found a rechargeable hand warmer that uses an Android phone hook up that works great, but the hot hands chemical warmers work well too. I wear a light weight glove with the little rubber gripper type dots on my bow hand and only my shooting glove on my other hand. Hands go in my hunting shirt pocket with hand warmer when the cold gets too bad.
Feet are tough for me. I have had surgery on both feet and ankles and my feet are always cold. I have been using the stick on toe warmers on wool socks with some success but would like to try the thermacell battery powered heated insoles, but of the guys I know that use them it is either they love them or they wasted their money.
Most people don't realize how much they sweat in cold weather and I have had people tell that they don't sweat in the wintertime. If you ain't sweating, your dead! Really important to take your time walking into your hunting area, not only to keep from spooking deer, but to keep your sweating down to a minimum. You may be chilly or even cold by not wearing your outer layer(s) on the walk in, but once you cool out for a few minutes and put the outer stuff on you may be surprised as to how warm you are and how long you can stay on stand. Good Luck!!