Dress for Success?

I used to know how to dress for job interviews. You put on a suit or a nice dress with pantie hose and pumps and you were all set. Today, you dress in business casual attire for most interviews and I am never sure what that means. The main problem, is neither does anybody else. I just spent three hours shopping for something to wear to an interview tomorrow. All I bought was a green button up shirt with a collar and a scarf that I picked up just because I liked it. The job is as a massage therapist at a spa/salon. If I were going to work on someone, I'd know just how to dress....black pants and a nice T shirt. However, I am not going to be working on anyone unless the person I talk with likes me enough to call me back for a second interview. Spas are places where appearances matter a lot. I can't look too casual or too dressed up for the job. I'll most likely wear the new shirt over black pants and maybe I'll figure out a way to drape the scarf over my shoulders or someplace (it's really long so I am not sure that I can carry it off.) At least I have a pair of green shoes that pretty much match the shirt. I'll just be glad when the interview is over.