In general I have dry hair. Especially in the wintertime my hair gets really dry and has a lot static, making it difficult to deal with. Treating dry hair can be frustrating and hard to figure out, especially when you're impatient to have smooth, shiny hair again! The best way to approach treating dry hair is to understand some of the causes and then you can go about treating it.
Dry hair can be caused by a myriad of things including too much sun exposure, chlorine, perms, hair color, and salt water. Another cause is the heat from blow dryers, curling irons, and straighteners. It makes sense then that a lot of the ways to treat dry hair are simply being away of the causes. For many of these causes you can take your own precautions. Wash your hair with shampoo that has SPF 15, wear a hat outside, wash your hair well after swimming, and buy products that are made for your hair (i.e. color treating shampoo).
One of the better ways to prevent and treat dry hair is by not washing it excessively. Washing it too much strips away the natural oils in your hair that keep it moisturized. While you want to definitely keep it clean, you shouldn't feel the need to go overboard, especially if your hair is already dry. Also, you can use a moisturizing shampoo and a conditioner to help with your dry hair. Deep conditioning is one the best ways to treat dry hair and can be done either in a salon or at home. At home you can put in conditioner and leave it in for 15–20 minutes. I actually have a conditioner that you're supposed to put in after you shower and then wash it out later; it's perfect for treating my sometimes static-ridden hair and makes it smooth and shiny.
Another good way to deal with dry hair is by maintaining a good haircut. When you manage your split and damaged ends, your hair looks better and it's easier to maintain healthy hair. One of the ways to treat dry hair that I'll bring up that we all probably don't want to hear is to go natural. Natural in this sense means no hair color, no perm, no blow dryers, no curling irons, and no straighteners. All of these things greatly contribute to dry hair and maybe for you (as for me) dry hair might be an okay price to pay for curls and color. The way to combat self-inflicted dry hair is by using products aimed at moisturizing; in most cases this offsets minor damage done by chemicals, blow dryers, and curling and straightening irons.
In the event you become exasperated about your dry hair just remember that it's a common hair malady, it's treatable, and chances are you did it to yourself!