It’s not just weatherproofing your front door that will keep your home nice and cozy in the winter months. Installing weather stripping around doors and using draft excluders under doors will prevent warm air wandering into unheated rooms.
USE YOUR CEILING FANS WISELY
Switching the direction your ceiling fan runs will force warm air back down into the room. To maximize efficiency, set the fan speed to low. You should also consider installing a fan at the top of your staircases to force warm air that rises through the floors back down to you. 
CLOSE YOUR UNUSED CHIMNEY
If you have a chimney and are not using it, make sure its flue and draft (if it has both) are closed. Open chimneys can suck the heat right out of your home. This is one of the biggest issues with open fireplaces – too much heat loss from the room. 
IMPROVE AIR SEALING AND INSULATION IN THE ATTIC
Like we mentioned earlier, much of a home’s energy efficiency during the winter is dependent on how well your attic is insulated and sealed. When either of those components is lackluster, that’s when your home gets colder and your winters more miserable.
A great place to start is by properly sealing and insulating your attic access, one of the most prominent sources of air leakage in your home. When your attic and attic access is not properly sealed, the warm air generated in the lower floors can easily escape into the attic and potentially through your attic walls.
This, coupled with identifying areas of your attic that are leaking and sealing them, is going to greatly reduce the amount of heat escaping through the attic. Properly insulating the attic floors will also greatly enhance your home’s energy efficiency. Blown-in attic insulations both work well in both winter and summer months, and multi-layer or reflective attic insulation is an innovative way of keeping heat out of your attic by reflecting back to its source.
Installing multi-layer insulation around your attic walls is also going to reduce ice dams. If your attic is attracting too much heat, it can warm up the snow accumulating on your rooftop. This causes snow to melt and cause ice dams, which can then cause excess moisture inside your attic. This can then degrade your batt or blown-in insulation. With multi-layer insulation, the heat will be directed back downstairs instead of up and outwards through the roof, eliminating the threat of ice dams and attic moisture.
Thus, when properly sealed and insulated, you can help create a much more controlled attic environment. This leads to increased energy efficiency through less heat and warm air escaping through your attic. 
 Just Energy Editorial Staff. "How to Keep Your House Warm in Winter: 10 Tips to Stay Cozy" Just Energy, 31 December 2021, https://justenergy.com/blog/how-to-keep-your-house-warm-in-winter-10-tips-to-stay-cozy/
 Neverman, Laurie. "25 Cheap Ways to Keep Your House Warm in Winter" Common Sense Home, 31 December 2021, https://commonsensehome.com/cheap-ways-to-keep-your-house-warm-in-winter/
 Greenrev. "How To Keep a House Warm In Winter: The Bulletproof Method" Yellowblue Eco Tech, 31 December 2021, https://yellowbluetech.com/2020/10/06/keep-house-warm-winter/