In the Northeast where I live, there is a moisture deficit all winter long. The heat is on everywhere you go, in the car and every store. WHat I see in the salon is that 99% of my clients have hair that is dehydrated. Hair that is dehydrated is dull, frizzy, and lacks bounce. Hair that does not have enough moisture will not style well and does not look good.
The fix: use a shampoo and conditioner that are extra moisturizing. I love Shu Uemera color protect products. The most important step is to put some type of milk or oil into the hair when it is damp. The dampness of the hair allows the product to be absorbed and do the most good. Even if you have fine hair, still put product into the bottom 6 inches of the hair. When summer rolls around again, switch back to a lighter shampoo and conditioner. If you are are heat styling, ALWAYS use a heat protect product on top of the oil you put in.