Find out where and when the casting call will be and prepare accordingly. If it's at night, wear an evening-appropriate outfit. If it's in a nightclub, look dressy. If you're auditioning for America's Next Top Model, bring a portfolio and wear your highest heels. If you want to get on Flavor of Love, be as hyper and bubbly as possible. Know what types of people these shows typically cast.
Be realistic. If you wear a tutu and tell the producers you're a fairy godmother, you'll definitely stand out. But, you want positive feedback, not just laughs. Be outgoing and friendly, but know when to tone it down.
Master your hidden talent. If you can tap dance or do the worm, more power to you. But, if your talent is somewhere along the lines of bending over backwards or sticking your tongue in your nose, know what makes you look the most exciting.
Look fabulous. Reality television producers are suckers for a beautiful girl and a hot guy. Wear your most flattering outfit, perfect your hair and smell really, really good. Flash a huge smile and be confident until it kills you.
Fit the role. If you're auditioning for Beauty and the Geek, know where you stand. If you're an average-looking individual, the producers probably won't call you back. It's not harsh, it's reality.
Impress the producers. Tell them a hilarious story and answer their questions with poise and charisma. They want to see what you're truly like and how you'll be on television.
Hand the producers your resume and a great photograph (preferably professional) as you leave. The more you appear to want a spot on the show, the more likely you'll be to get one.