Jason Backe, Clairol's color director, shares what he knows about how to get salonlike results on your own.
In the Store:

1. Decide exactly what you want. To cover gray, you need a permanent dye, like Garnier Nutrisse Nourishing Color Treatment ($7.50). Time to touch up your roots? We love Clairol Nice 'n Easy Root Touch-Up ($7), a permanent dye that comes with a tiny application brush. For a slight shade change, try a semipermanent dye, like L'Oréal ColorSpa Moisture Actif, $8, which slowly rinses out over about four weeks.
2. Choose your color. Go no more than two shades lighter or darker than your current color. And use the chart on the back of the box to determine the shade you will get to from the color you have now.

1. Apply semipermanent dye to damp hair but permanent dye to dry hair.
2. Smooth Vaseline along your hairline, on your ears, and on the back of your neck to create a barrier that will keep dye from staining your skin.
3. If you're going darker, start applying color on front sections (where it's usually the lightest) first. If you're lightening up: Start in the back. 
4. Leave the dye on as long as the instructions indicate—not a minute more.

Yes, it can be done! Three at-home makeovers you won't believe

Plus, two new at-home kits make the process even easier:

Clairol Perfect 10 Haircolor Clairol Perfect 10 ($14)

This permanent haircolor uses a new lightening system (part of the permanent coloring process) based on hydrogen peroxide and the amino acid glycine. Because it doesn't contain the ammonium hydroxide that's in most formulas, it smells a whole lot better and has a lower pH—which means it's gentler on the hair, says independent cosmetic chemist Mort Westman. Best of all, the new technology allows this dye to get the job done in 10 minutes (compared with the usual 20 to 30).
fekkai salon color
Fekkai Salon Color ($30)

Most home kits come with an applicator tip that lets you squeeze the color directly onto your hair; this can make an even application tricky (and drippy). Fekkai's first-ever color kit comes with a bowl and brush just like the ones colorists use at his salons. The tools allow you to mix the color very thoroughly and work it through each strand—they also make it easy to use the product just for a root touch-up. The new line's 20 shades, from pale blonde to soft black, were created based on input from top Fekkai colorists.