1. Only wash your hair 2-3 times a week. This will prevent your hair from drying out and becoming damaged. Also never leave the house with wet hair.
2. Once a week treat your hair to deep conditioning. Due to dry heat in the winter your hair needs to be replenished with moisture to keep you looking your best.
3. Make sure you are still getting regular haircuts. It is very easy to get dry split ends in the winter but you can prevent that by getting a trim every few weeks.