Step 1: Figure out your commitment level.
You can immediately narrow the field by deciding how different you want your hair to look—and how much time (and cash!) you're willing to devote to color maintenance.
For a can't-be-missed change: Try a permanent color when you want to go up to two shades lighter or darker, says Clairol color director and New York City salon owner Marie Robinson. These formulas are also your best bet if you have lots of dye-resistant grays. Permanent dyes require a bit of work, though: Since they grow out instead of fading, you'll likely need to do monthly touch-ups to conceal root regrowth.
For a subtle pick-me-up and extra shine: Opt for a demi-permanent formula. These shades fade slightly each time you shampoo and completely wash out in about 28 shampoos, leaving no roots. Experts say this type is a great choice for those looking to minimize damage or to simply enhance their natural color (for example, if brassiness is peeking through your brown strands, a demi will cover it up). One caveat: These formulas really only work for those wanting to go darker, says Robinson. Because they don't contain ammonia, they won't lighten your current hue. And you'll have to reapply it monthly to maintain the look.
For a noticeable enhancement with few strings: Try highlights. They're spread out over your head, so they grow out without showing a distinct line of demarcation at the roots. "Highlights are great for those who want to color once every three months," says New York City salon owner Rita Hazan. They require less commitment and enhance your natural color, she adds. One drawback: At-home kits don't work well on very dark hair, which requires a higher level of lightening, says Johnathan Gale, a colorist in Los Angeles. For you, a salon trip is in order.
Step 2: Determine your skin tone.
To find the shade that will bring out the best in your complexion, you need to know your undertones. How to uncover them:
If you're going for allover color: Put on a white shirt, remove all traces of makeup, and drape a white towel over your hair. Stand in front of a well-lit mirror and take a good look. If your face looks pink or red, you've got cool undertones. See peach, olive, or gold? You're warm. If obvious colors aren't glaring back at you, or if you have hints of both, you're neutral.
If you're doing highlights only: Peek at the flecks in your eyes to determine the streak hue that'll draw attention to them, says Canale. If yours have hints of gold or amber, they're warm. If you see blue, silver, or gray, or if you have brown eyes with no flecks at all, they're cool. Experts say that while eyes alone can guide your streaks, your skin should always dictate your overall color (a helpful tip for those with warm eyes and cool skin…or vice versa!).
Step 3: Start shopping!
In the store, opt for colors close to what nature gave you, then look for certain keywords for a face-flattering match.
For cool skin tones: Aim for ash or neutral shades (you'll see the letter A or N on the box). These lack red or gold tones and counteract pinkness in your skin, says Robinson. Blondes should look for color descriptions like champagne or beige; brunettes can hunt for chocolate or espresso hues. Dying to go red? Steer clear of copper or cherry descriptions and go for a medium auburn: This brownish red will give contrast to rosy skin, not match it. Try L'Oreal Paris Sublime Mousse by Healthy Look in Spicy Auburn Brown ($10, at drugstores).
For warm skin tones: Give your complexion a healthy, natural flush by adding golden or reddish tones to your hair (look for G or R), advises Hazan. Blonde shades in this color family include honey, strawberry, and copper; brunettes should try golden brown, chestnut, or mahogany. Try John Frieda Precision Foam Color in Deep Cherry Brown ($13, at Target).
For neutral skin tones: Middle-of-the-road skin gives you more leeway to be a color chameleon, and you can choose a shade based on preference, says Hazan. (Just take some inspiration from famous neutral girls Drew Barrymore and Leighton Meester!) Go for a look that best fits your personality and upkeep level.
Finding your highlight hue: If your eyes are warm, weave in a similar tone like butterscotch, toffee, or copper to make your peepers pop. Platinum and auburn shades flatter cool eyes. Look for a permanent formula like Couture Color Luxeblend Ammonia-Free Creme Hair Colour ; the brush inside helps you target specific areas (rather than your whole head) for a natural, sun-kissed effect.