To keep your hair gorgeous and damage free, ditch the habits that do the most damage:
Chemical Processing - Bleaching, perming or chemically straightening your hair can cause all sorts of of damage to your hair from stripping it completely of its pigment and moisture, to changing the chemical structure of the bonds that keep your hair healthy and strong. Avoid these processes as much as possible.
Highlighting/Coloring - While not quite as bad as bleaching, you are still using chemicals to alter the appearance of your hair. This can cause your hair to become weaker, dull and dry.
High Heat Styling - Using temperatures over 300 degrees to style your hair will cause massive damage. High heat depletes your hair of moisture and causes the hair structure to melt or become weaker.
Over Styling - Styling your hair too often can cause damage. Tight braids or ponytails with tight bands will snag or break hair. Excessive use of styling tools and products can strip the hair of moisture. Over brushing your hair can cause damage, as well as attempting to brush or handle your hair too much when it's wet and at its most vulnerable state.
Overuse of Products - Using too many products in your hair can cause a damaging buildup that prevents your hair from retaining moisture, or even can cause it to dry out. Washing your hair too frequently, especially with products that have harsh chemicals, will strip your hair of its natural oils.
Hair Extensions and Weaves - Hair extension can cause damage as well. They irritate the scalp, pull on your natural hair, and cause hair to break, even damaging the follicle.