When choosing a lip color, keep it light to give the illusion of bigger lips, advises celebrity makeup artist and founder of GlossiGirl Cosmetics Stephen Dimmick. "Darker colors only highlight the natural size of your lips," he says. "So if you don't already have full lips, a dark color will accentuate the thinness."

"Instead, choose a shade similar to the color your lips blush naturally," says makeup artist Liz Washer. That means roses, berries and caramels, depending on your natural skin tone. (Try: Yves Saint Laurent Beauty Rouge Pur Couture Vernis a Levres Glossy Stain in Rose Vinyl, $36, or Bobbi Brown Sheer Lip Color in Natural Pink, $27).

If you're going for fuller lips, liner can be your best friend -- but aim for subtlety in both color and technique. "Over-lining the lips with a dark shade can look clownish," Washer says.

Instead, for bigger-looking lips, choose a lip pencil close to your natural lip shade, and line along the very edge of your natural lip line with short, sketching motions. You want to emphasize the Cupid's Bow (that's the dip in the center of your top lip), as well as the fullest part of your bottom lip, all the way to the outer edges (which often get lost). "Finish by filling in the entire lip with pencil and applying lipstick on top, blotting for a long-lasting finish," Washer says.

If you want to over-line for extra fullness, use your pencil to build color right outside your natural lip line in the center of the bottom lip and on either side of the Cupid's bow. "Don't over-line around the entire perimeter of the mouth, as it can begin to look fake," says Washer. (Try NYX Cosmetics Retractable Lip Liner in Soft Pink, $4.49, or Make Up For Ever Aqua Lip Waterproof Lipliner Pencil in Rosewood 2C, $19).

Like dark lip colors, mattes also tend to accentuate the smallness of one's mouth. To make lips look bigger, add shine. "Tinted lip glosses and balms add a reflective quality to your lips," says Dimmick, making them catch the light and appear plumper. Burt's Bees Tinted Lip Balm, $7, and Tarte LipSurgence Lip Gloss, $19, work perfectly to create that plump, patent finish.

Across the board, makeup artists' trade secret for creating bigger lips is this: Use two colors. When applying your lipstick, use a lighter shade in the middle of your bottom lip and a slightly darker shade everywhere else. "It's kind of like contouring for your lips," says makeup artist and Younique presenter Christina Nicholson. "Color in the middle of your bottom lip with the light color [you can also use a white eyeliner here], then use a lip brush to blend it with the other pink or red color you're using," Nicholson explains.

For an extra-big pout, you can also restrict shimmer or gloss to this part of the lip, adds Dimmick.

If you're one to whip out a dark red or purple, but still want a plump-looking pout, there's a way to work around the rules. To keep your lips looking full, "don't take a dark color all the way out to the outer corners of your mouth," says Dimmick. "If we shorten the width of the mouth, it will give the slight illusion that your lips are vertically fuller."