I’m pretty new to hunting, but not to keeping warm in the outdoors. In any winter sport, there is nothing worse than cold feet.
I find when I am actively walking, cold feet are not a problem. It's when I stop/get to my stand the coldness starts. A few things that I do to avoid cold feet when staying in one place whether in a stand or just staying put:
1. Avoid just standing. It seems to push the blood out of your feet and speeds up the numbness. Stomping your feet warms them up but is not conducive to quiet hunting. Best to find a seat and put minimum pressure on your feet.
2. Foot warmers. Not the electric kind but the chemical kind. It doesn't matter whether you use the hand warmers or feet-specific warmers, as long as they fit in your boot. The trick is to locate the warmer right where your toes are, either above or below (or both). It's the extremities that get the coldest so put the heat there. I picked up a bunch of them for a buck a pair at Wally World. They really work.
3. Wool socks. At least 80% wool is best. None of the new stuff works as well, IMO. Some poly-pro liners to wick the sweat are good, but it’s the wool that keeps you warm, even if wet. I had a really thick set of synthetic socks that started off great, but once they got a little wet, it was like I was barefoot.
4. Spare set of socks. I have sometimes had to hike a ways to get where I want to be, working up a sweat to get there. It’s nice to have a dry spare pair to change into, or put over the socks you wore to your destination.
5. Concerning the type of boots, something that breathes is best, but more important is how they fit. Too tight cuts off circulation, which in turn leads to numbness/cold. Learned this by skiing in too tight ski boots for a day. I would rather have something a bit loose (not too loose) to allow circulation both in and around your feet.
There are likely other things but I think the above will keep you in good shape.