Sure, pouty models might look gorgeous and all, but who really wants to strike up a conversation with someone who looks like she's itching to throw punches? And have you ever seen a frowning contestant on "DWTS" (when they're not receiving their scores)? A smile is the key to a great performance.
Increase your face value (get it?) by flashing that megawatt smile you were born with. If you're self-conscious about your smile, it's easy enough to use an over-the-counter whitening system or even have minor dental work to give your smile the oomph you desire. All the diamonds or sparkly outfits in the world can't even come close to the natural transformation that a radiant smile provides, so be sure to break yours out from time to time.