To begin, always brush out any tangles in your hair before you shampoo. The minute water hits tangles, it can lock them in, making it difficult to comb out, and causing breakage and weakening hair. Always pay attention to the underpart of your hair; women often don't realize how tangled this area can be. 

Apply shampoo at the root area and begin to work it out gently through the ends. Try to keep your hair in the same direction as the flow of the water to prevent tangling. A vigorous scalp scrub may feel good, but it can cause snarls down the hair shaft. Just let the shampoo run down the shaft. 

After rinsing, apply conditioner to the ends of your hair. (Yes, this is the opposite of how you apply shampoo. That’s because most people don’t need conditioner at the newly grown roots; they need it at the older ends.) Most importantly, comb the conditioner through with a wide-tooth comb, starting at the ends and working up the shaft. Last thing you do is rinse, again in the direction of the water flow. After getting out of the shower, pat your hair dry with a towel and carefully comb it out from the ends up.

Now you have perfectly clean and conditioned hair ready for styling!