I just got my first look outside, and it's deep. My phone app says 14 inches and 4 degrees with crazy wind. First off, I know what my workout for today is. I'll be throwing and pushing snow around for hours. My first rule is to pace myself (actually, the first rule is to finally break down and buy a snow blower). Second rule, go back and forth between jobs, whether this is carrying snow, tossing it over my shoulder, or pushing it along the ground, I try to go from one jog to the other whenever I need to.
Always be doing something. If you're moving from point to point, you should always be pushing, or carrying a big pile someplace. Don't waste energy and time by walking back to your original starting point without moving snow.
Rest completely when needed. Just taking a five minute break, can give you lots of legs, as you allow yourself to catch your breath and recover. Always be sure you rest and rehydrate after hours of shoveling just like you would after a really long, intense workout.
Stay warm, enjoy the physical energy expended.