10 Commandments of Sinfully Rich Hair Color

By Genevieve Monsma

Tempted to try a DIY dye job? Whether you're headed toward blonde, red, or brunette, don't even crack open the box until you've read these expert tips.

1. HONOR THY hue
"Use your current color (even if it's dyed) as a gauge when selecting your formula — and never lighten or darken your hair more than two shades at one time," says Rachel Glenn of Chicago's Prink Salon.

2. THOU SHALT KEEP THY cool
Lightening tresses with a "warm" formula may leave you brassy. "Opting for a color described as 'cool' or 'neutral' is a safer bet for first-timers," says Jason Backe of Manhattan's Ted Gibson Salon.

3. THOU SHALT NOT skimp ON DYE
Imagine running out of dye halfway through color application. Not good. The amount in most kits is sufficient for the "average" head of hair (about shoulder-length). So, cautions Patty Slattery, director of L'Oréal Technical Center, "If your locks are longer or very thick, stock up."