Use a humidifier at night
Your home heating probably keeps the air very dry, especially in winter, and that can dry out your hair. Putting moisture back into the air will help your hair from becoming more dry and damaged.
Let your hair down
If you usually wear your hair in a ponytail, take it out for a few hours a day to give your hair a break. Also, try not to pull hair back too tightly. And never sleep with any sort of accessories in your hair.