Confidence is key. As soon as you walk into the building you must portray confidence. Have it begin with the receptionist that you check in with, with the people you make eye contact with, and with everyone that you have an opportunity to speak to. Even if you have butterflies in your stomach, well, you’re an actor aren’t you? So your acting begins as soon as you step through the door.
Eye contact is important. Stay focused, if your audition includes a reader, passing the lines to you, keep eye contact with that person. When you cut your eyes away from the reader, the audience, the viewers, the camera, it gives the impression of an immediate lack of confidence.
I’ve mentioned look your age before. Keep your appearance and clothing age appropriate. Avoid wearing makeup, kids don’t wear makeup to school, at least they shouldn’t depending on the age. Even if you are a teen actor, don't pile the makeup on too thick. Keep it light, natural looking.
What does your hair look like? Is it neat, groomed, falling into your face, and age appropriate? Everyone wants to grow up too fast, except once you are grown up. Casting agents don't want a 12-year-old walking through the door looking like they are 16.
Wear solid colors, consider colors that highlight your eyes, hair color, and completion. Pick out your favorite audition clothing and keep them only as audition outfits so that they don’t wear out too quickly. Avoid patterns, stripes and dots, and especially clothing with logos. No hats, and only wear your eyeglasses if you can’t see without them. And no crazy costumes, unless the casting called for them.
Think about how you can stand out from the rest of the crowd that shows up for an audition. Maybe it will be in your strong delivery, your confident voice, the way you hold your head high, or your body stance. Think about your gestures, what is the side calling for in the character. Work on different emotions, body and hand gestures at home that fit varying emotions and as I always say… Practice, practice, and then practice some more.
More importantly, have fun, stay as relaxed as possible, and enjoy the experience. Think of everything you do as a stepping stone towards your goal of an acting career. And if you don’t get the part, that is okay, a lot of people who attend castings may not get the part, otherwise, everyone in the room would be cast. So instead of being discouraged, think of it as a step closer.