I have seen great benefits from this tip. When you are finishing your shower, turn the facet to cold for just a minute and rinse your hair. Rinsing with cold water gives you shiny hair. Here is why:
Thirty seconds under cold running water will help seal the cuticles on the hair shaft, trapping moisture in the hair and creating that beautiful hair commercial shine. Your hair will instantly feel softer and silkier. See complete article here.
Also, the cold air button on your dryer has a similiar benefit. I always finish drying my hair with cold air. It seems to do the trick!