Put your best foot forward, literally. There's a reason that most red-carpet pics looks the same—starlets with their hands on their hips, one leg slightly forward, and the lower body angled away. That said, Ernst cautions against using the same pose too often.
"Don't do the hands-on-hips thing all the time! It looks affected. You need to mix it up." She advises taking practice shots of yourself, either with a friend or a self-timer, and seeing what looks most natural and flattering for you. A few pointers to get you started: Keep your arms away from your body to improve your posture and make them and your waist look smaller, slightly arch your back (think Victoria's Secret models), and remember that whatever is closest to the camera will look the biggest.