Dark rule #1: Start with semipermanent color, especially if you're worried about dyer's remorse. It stains only the surface of hair, so it's easier to lighten up again if you change your mind.
Dark rule #2: Think twice about going jet-black in one fell swoop. You may love it on a celeb, but it can look harsh if you're fair-skinned. "Ease into it," suggests Rona O'Connor, co-owner of Lukaro Salon in L.A., "by trying a dark brown shade first."
Dark rule #3: Remember your brows! Too-light ones ruin the illusion of being naturally raven-haired. Use a dark brow pencil.
Light rule #1: Forget allover highlights. "It's so outdated and looks unnatural," says O'Connor. Instead, stagger the highlights so it looks like you were born with those sun-kissed streaks.
Light rule #2: Strengthen your hair. To prevent breakage, a common bleaching problem, do a protein treatment monthly. Try Redken Extreme CAT Treatment ($13, redken.com for salons).
Light rule #3: Make a salon appointment if you want to go really, really blond. For a DIY job, it's risky to lighten up more than two shades beyond your natural color--you could get brassy.
