Deeply pigmented beverages such as soda, coffee, dark tea, and red wine can stain teeth, as can foods like blueberries, cherries, and soy sauce. "If it will stain white cotton, it'll probably stain your teeth," says Kenneth Kerman, a dentist in Brooklyn, New York. Beware of white wine, too. All vino -- whether colorless or red -- can roughen up tooth enamel and make your smile more susceptible to stains.

"The dentist's office provides the best chance for successful whitening if you're on a short timeframe," says Elisa Mello, a cosmetic dentist at NYC Smile Design.

At around $800 a pop, one in-office whitening session can get teeth two to three shades lighter. A gel is carefully brushed onto teeth and subjected to a bleach-activating light. Supplement this with a take-home kit (to be used every night for two weeks), and you can lighten your teeth up to five or six shades. For a less expensive (though still effective) option, pick up over-the-counter teeth whitening strips that "keep the brightening solution closer to teeth longer than toothpastes or rinses," says Kerman. By the end of the month, you'll be able to see a three- to four-shade difference.

Most people don't have perfect symmetry to their faces or smiles, so one pose is more flattering than others. Before the big day, look at some recent pictures of yourself, or practice tilting your head at different angles in the mirror. Then you'll know which pose to strike at picture time.

Lipstick clings to dry, flaky spots on your mouth (read: not pretty). To keep your lips smooth, "use a soft electronic toothbrush to gently buff away dead skin," says Sandy Linter, a New York City makeup artist. "Then cover your mouth with a thick balm and sleep with it on overnight."

Choosing the right lipstick can make your teeth look whiter instantly. Steer clear of oranges, salmons, peaches, browns, and corals -- they give teeth a yellowish cast -- in favor of red or pink sticks with cool or blue undertones. The blue counteracts the tinge of stains and makes your smile look shades brighter.

Though matte formulas last the longest, they also tend to absorb more light -- and that can make your teeth appear darker. Instead, wear a creamy lipstick that has some shine or shimmer to it, or sweep on a gloss. It will reflect light and make your smile look brighter.

Just before a picture is snapped, swish a sip of water around in your mouth, or sweep your tongue across your teeth. When they're hit with the light from the flash, they'll sparkle.