These are just some things that I always incorporate in my outfits:
First thing is to find out the culture inside the company so you can get a feel for what woud be appropriate to wear for your basically test shoot. The whole thing about interviews, is looking like you already belong without overdoing it (to me). The only thing they will look at after that is your qualifications as far as handling your tasks.
Since most people are about to graduate and are looking for jobs, I thought I would help out a bit. Especially in Washington, DC where there are so many companies, it is hard to avoid looking like you do't belong when going to a job interview. Most interns around this area just wear full on suits, which is pretty much like putting a bright target on you that says "intern" or "newbie" and we don't want that.
So over the next two weeks I will do posts on different interview appropriate outfits according to the type of environment (if that makes any sense).
In the meantime tweet me @theworkette