Hair Highlights

Highlights consist of selecting small or thick strands of hair that are then lightened at least 2 shades lighter than the rest of your hair. Highlights should compliment your natural or artificial color. You should never go more than 3 shades lighter then the rest of your hair color. The object of highlighting is to give you a sun-kissed look and to bring depth and light to your overall color.
So if you want to achieve salon perfect results at home when you highlight your hair, here's what the pros say:

• Use a clarifying shampoo on your hair at least two days before coloring.
• Never shampoo the day you color. Haute hair
• Check the expiration date on the package. And once you mix the color, use it right away!
• Toss out the brush that comes in the box and buy flat 1/2 and 1/4 inch acrylic brushes. These brushes, used by artists, are available at art supply stores (they'll give you better control and more natural-looking results)
• Make sure you have on hand a pair of good, tight-fitting latex gloves (the ones that come in the package don't always fit well).
• Start from the back of your head and work forward. By working from back to front, you won't smear the pieces in front by having to reach over them to do the back.
• Apply the highlights only to the top layers of your hair. By leaving the hair underneath alone, you'll create depth and a sun-kissed look that looks completely natural! 

source:http://free-beauty-tips.glam.com/hair-highlights.html