Interview success depends on mastering not only what you say with your words, but also what you say with your demeanor and actions.
Attitude: Experienced recruiters pick up on attitudes quickly. You don't want to be perceived as arrogant (I'm totally qualified for this job) or disinterested (I'm not all that excited about the prospect of working for you). Show your savvy by matching your demeanor to the context of the interview and the frame of reference of the interviewer. You may not get it 100% right, but your efforts will be noticed and will have a positive benefit. Just one word of caution: never forget that an interview is a professional interaction, not a conversation between friends. Your attitude can be cordial without being inappropriately casual.
Behavior: Actions speak louder than words! You show disrespect for the interviewer and the process if you act unprofessionally. Inappropriate dress is one of the most damaging interview mistakes a candidate can make. Additional things like poor posture, lack of eye contact, fidgeting, arriving late or forgetting to turn off your cell phone all send the message that you are either completely clueless about how to behave or you know what you should do but just don't care. Neither goes over well in an interview! Instead, try reading a couple of internet articles about appropriate dress, and ask someone in your career services office to double check your outfit. And while you're at it, doing mock interviews with a career professional will help you evaluate the non-verbal messages you send.
Communication: The interview is not a social conversation. What's completely appropriate among friends may be completely inappropriate in the interview. Slang, crude talk, babbling or stammering all represent you in a less professional light. Talking negatively about previous employers or other educators is also a bad idea. Be sure you can say what you need to say clearly, concisely and professionally. In fact, practicing out loud gives you a much better feel for the effectiveness and appropriateness of what you will say in an interview. Show respect in the way you communicate, both face to face and via email. One final warning: your online profile (Facebook, Twitter) is also a way you communicate about yourself. Clean it up before you start applying or interviewing.
No one is suggesting that you pretend to be someone you're not, but successful interviewing matches the message with the context of the interview. Working to eliminate the places where differences might negatively stand out will help you survive and THRIVE in an interview.
Assistant Director of Programs and Training
Center for Calling & Career
Northwestern College, St. Paul, MN