Your appearance matters. A casting director’s first impression of you, can make or break any casting call opportunity. The important thing here is to stand out, while maintaining a professional and business-like attitude (which, believe me, is not an easy task to do). Treat every casting call like a job interview- come prepared, act confident, and dress for the part. If the director wants you to come in costume, then by all means, do so. Just remember that you should be comfortable in what you’re wearing. If you’re auditioning for an action movie (like the Bourne series or the Hunger Games), then wear something you can tumble around in. Don’t wear tight-fitting clothes or anything that is too revealing. And unless the director wants you to look like a hobo, make sure that you are properly groomed (brush your teeth, shave, clip your nails, etcetera)
That movie casting call could open a lot of doors for you. Do your best and look your best.