At your singing audition, remember that other people are looking at you from the minute you walk in the door — not just when you sing. You want to show off your body and look great in your outfit. If you’re auditioning for a musical or a production with a specific character, think about what the character you’re auditioning for looks like.
You want to suggest the character but not dress exactly like the character. For an opera audition, you want to look classy. Wearing jeans and your cool tennis shoes is fine for a pop-rock audition, but not for an opera audition. If you’re not auditioning for a character role, choose an outfit that shows off your personality and highlights your figure.
Also remember that you may not be cast the first time you audition, but you still need to make a good impression. Sometimes directors ask you back to audition again to make sure that you’re outstanding every time you audition, not just on a good day. Though your mother may not like it, wear the same outfit for the callback.