Casting is the process of trying out talent to book on a particular project for TV, Film, Commercials or Theatre. When a performer wishes to be cast in a production, that performer will display their talents to a casting director or producer of the project. The casting director is the person running the try-out and will have a heavy impact on choosing the right talent for the production.
When attending a casting, always bring your headshot and resume with you. Arrive thirty minutes before your scheduled performance and be prepared, either by memorizing the song you are singing or knowing the lines you will be acting. Be polite and professional to the casting people involved in the tryout and never ask a casting director if you got the part; don't call them, they'll call you. If you attend a casting session pre-pared, professional and excited to perform, you are already a success.
After waiting perhaps hours, finally you're auditioning. The casting director has now seen many other people ahead of you, which means he/she and anyone else is likely to be tired, bored, and irritable. Make the director's job easy and you increase your chances of having a successful audition. By not being ready, talking too much, and so on, you're making the job harder and may seriously kill any chances of your getting a role.
You're briefly introduced; "(your name here), auditioning for the role of: Girl in Skate Shop".
Whatever you may be auditioning for, they will ask for your headshot and resume. You might pass out multiple copies. They may take a digital photo so the casting director can review all the people who were auditioning that day. Smile and look your very best. If you don't currently look anything like your headshot, get a new headshot. Now wait for your cue, and show them what you've got!