Pick highlights that are only one or two shades lighter than your natural hair color. The more subtle the shade, the less possibility for something to go wrong.
Match the tone of your highlights to your hair and skin tone. If you have warm-toned skin and reddish-brown hair, go for golden or strawberry blond highlights; for cool-toned skin and muted browns, try a honey or ash shade.
Deep-condition your hair a few days before coloring to lock in moisture and seal up hair follicles. Dry, brittle strands are more porous and may absorb more color than you want or absorb it unevenly -- and that leads to streakiness and unwanted colors.
Use a light hand when applying the highlights. Gently sweep the formula from root to tip, and leave dark pieces untouched in between each highlighted piece. Remember, the lightening process starts as soon as you begin applying, so do your first highlights on the pieces you want to be lightest -- most likely, this will be the pieces toward the front of your head.
Watch the clock. If you wash the formula out too early, the color may not have a chance to develop properly, leaving you with orange strands -- but if you leave it on too long, it'll overdevelop and cause the same effect. Follow package instructions to a T and be sure to rinse the dye out completely.
Keep your hair looking shiny and reflecting color properly by conditioning often. Use a conditioner designed for color-treated hair daily, and deep-condition once a week if your hair tends to be dry.
Have a friend help you apply the highlights -- those strands at the back of your head can be hard to reach on your own.
Avoid those sun-activated highlight sprays -- they work best on blond or very light brown hair and tend to cause orange streaks in darker shades. And once the tiger stripes appear, they're tough to cover up.