Sit comfortably and make your expression pleasant. At first the interviewer will do the talking. He or she will often begin with some small talk. This may seem a very subtle point, but it immediately establishes a comfortable atmosphere. Don't ignore the person who takes you in to the interview.
Many interviewers ask their secretary or receptionist what they thought of the applicant.
It is also important to learn the interviewer's name. Use it more than once during the interview. People like to hear the sound of their name. How you sound is just as important as how you look when you apply for a job. Try to identify any 'wince' words you might use, such as 'you know'.