Ultimately the best way to survive a long-term power outage during the winter is to keep your house as closed up as possible and stay indoors. Only go outside for an emergency or to bring in firewood. Minimizing the amount of times that your exterior and interior doors are opened will help keep the heat that you are able to generate inside one main room.
You will also want to wrap yourself in blankets and, if possible, make warm foods and beverages. Steer clear of alcohol, though, because this will actually make you much colder in the long run. Be sure to keep your pets under the blankets with you as this will protect them and will add extra body heat that everyone can benefit from.
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