Sometimes it's unavoidable; you have to sell in wintertime when the snow is on the ground and it's freezing out. Many homes don't show as advantageously in the winter as they do in the summer when plants are blooming and the temperature is comfortable. Your goal is to stage your home specifically for winter, making it a haven from the cold and snow.
If you stage your home yourself, you can find a lot of information in books on the subject and on the internet. Or, for a nominal fee, you might be able to get some suggestions from a professional home stager to guide you along.