ABC Rebecca Romijn's practiced smile comes from years of modeling before taking on television and the big screen.

Natural smile takes practice

When it comes to smiling for the cameras, only practice makes perfect and the mirror is your friend. New York-based cosmetic dentist Dr. Jeff Golub-Evans shared some suggestions for a ready smile when the paparazzi are swarming:

» Practice smiling with your teeth slightly parted (one pinky finger breadth). You'll show more white teeth and your smile won't look forced.

» If your upper lip is full, don't thin it by smiling too broadly. Just smile enough to show your teeth.

» If your upper lip is thin, smile so that the bottom edges of your upper teeth touch your lower lip. The visual impact will divert attention from your upper lip.

» Many models learn to pose a smile by just opening their mouths and not wrinkling their eyes.

» Bright red lip color shows off white teeth. Magenta can make them look more yellow. Rose, pink or sheer usually doesn't offer enough contrast.

» A tan always makes light teeth look whiter.

» Wet your teeth so they sparkle.

» If you have any minor defect in your smile (a stain, crack, etc.), wipe some petroleum jelly on it. The aberration will be diffused.