I'm assuming you mean on stand, moving around I never have trouble staying warm. Sitting on stand though, that's another story. Since I perspire easily I carry as much of my clothing in as possible, sometimes even change my base layer when I get to my tree or blind. If I can avoid getting all sweated up I'm in pretty good shape. Clothing consists of merino wool, wool sweaters, bibs, jacket and most important of all, neck gaiter and good hat. No secrets there. I stay home when the clothing required to keep me warm makes shooting impractical. Then I like the idea of warm indoor activities for the evening.
Aside from good clothing, I do isometric exercises while on stand. I stand up as much as possible because I find it much warmer than sitting. You use more muscles and it's muscular activity that generates heat. I will do slow half squats, just a few inches and hold. Not enough to generate noise or be busted for movement. It's surprising how fast you warm up with just a little bit of exercise.