Dress for success. The best rule of thumb is to dress for a position just above the job you are applying for.
Be on time. Although it is important to be on time, do not arrive more then 10 minutes before the scheduled interview.
Be sure to bring a briefcase or leather-bound folder. Be prepared to take notes and have a place to store several unfolded copies of your resume and cover letter
Upon leaving the interview, make sure you get business cards from all the people you met so you can send thank you notes. Send the notes immediately.
Wait at least five business days to hear from the interviewer before you call them.