First, comb your hair thoroughly before bathing, wet hair is more delicate than dry so you have less chance of causing damage if tangles are removed beforehand. Next, heat can severely damage the hair. While hot water isn't nearly as damaging as a blow dryer or direct sun, it still takes a toll on the hair. To avoid this, adjust the water until it is pleasantly warm and no warmer. Steaming hot showers feel great and can certainly be indulged in, but it's best if your hair is left out of the direct path of this very hot water so consider cooling it down a little while washing.
Next, take into account what type of hair you have before shampooing. If your scalp is oily but the length is dry, don't directly shampoo the entire length. Instead, get a good lather going and then apply shampoo to the oily part of the scalp only, then rinse. The shampoo flowing down the length when rinsed will be plenty to remove surface dirt. Do not fold your hair up and "scrub" it with the shampoo as this can cause a lot of tangling and damage. Let the hair lay flat as much as possible throughout the wash.
To condition, start from the ends and work your way up. Make sure the ends, which are more prone to damage than any other part of the hair, get a generous amount of conditioner. Gently massage the product into the length of the hair, but only brush a little bit on the scalp area if you have trouble with an oily scalp. Let it sit for 1-3 minutes, then rinse. If you'd like to bring out the shine in your hair a little more, rinse it in cold water; cold water helps the cuticle lay flat.
Now it's time to dry your hair. Twisting the length into a rope and wringing the excess water out of it can stretch the hair, weakening and breaking individual hairs. Instead, you can grip the length near your head and work your way down, gently squeezing the water out.
Towels are not meant to rub the water out of hair, and rubbing against the hair can cause severe tangling as well as catch hairs and pull them out. For best results, gently press the hair in between two parts of the towel to draw even more water out.
If you use a leave-in conditioner, this is the time to apply it. If the package instructs you to comb your hair to disperse the conditioner, be sure to start at the ends and use caution when combing. Wet hair stretches very easily so snagging on tangles is likely to cause damage. Brushes are generally damaging even under the best conditions and should never be used on wet hair.
We've discussed the damage heat can do, so if you use a blow dryer take extreme care with it and do some research on ways to reduce the damage. Bear in mind that no matter what method you use or what kind of heat protection you apply to your hair, it will sustain some damage with a blow dryer.
Finally, hair does not necessarily need to be washed every day. Washing with shampoo too often can strip the hair of the oils it needs for good health, often a rinse or light conditioning by itself is plenty to keep hair looking great in-between shampoos. Alternatively, if you desire a little more detergent power you can dilute shampoo in a small bottle of warm water and squirt it on your scalp for a light cleaning.
