If you wear a beard or mustache make sure it is neatly trimmed. Use only light aftershave, NO cologne. Fingernails should be clean and neatly trimmed. Carry your resume and transcript in a folder or portfolio case. You want to look professional at all times.
Women Avoid fads and high fashion.
Your appearance should be conservative. When in doubt, Don't. You want the interviewer to concentrate on your abilities rather than your clothing. Be sure that you feel comfortable in the outfit. Try it on before the interview to decide on the proper accessories.