Summarize:

Dying, straightening and teasing can all cause harsh damage to your hair.  In order to keep your scene hair looking stylish and healthy, make sure you take steps to care for it. Try to find products that are meant for your type of hair (such as oily hair, thick hair, curly hair, and so on).  If you've dyed your hair, buy shampoo that's specifically meant for color-treated locks.  It will help your dye job last longer. Also, if you have dyed hair, wash it in water that's as cold as you can stand.  Hot water will make your dye fade out faster, as well as making the shade slightly off. If possible, try to find shampoo that doesn't contain sodium lauryl sulfate or sodium laureth sulfate.  These compounds are alcohols that dry out your hair. Schedule a deep conditioning treatment for your hair on the same day every week.  Browse around for one that suits your hair type and budget.  If you need something simple to start with (and you live in North America), try Aussie 3-Minute Miracle. Find a product you like, and use it religiously whenever you apply heat to your hair.  Your ends will thank you for it. The only way to get rid of split ends is to cut them off.  If you notice your ends starting to fray, book an appointment with your stylist or trim them yourself.  Either way, make sure the cut is high enough to remove all of the damaged hair. You're probably going to use a lot of styling product if you want to have scene hair, and it's important to wash it out.  Every other day or every third day should be sufficient.
Pay attention to damage control. Use a quality shampoo and conditioner. Deep condition your hair once a week. Always use a heat protectant when you blow dry or straighten your hair. Trim up split ends. Wash hair regularly.