Body language can affect an interview because employers are always looking for insight into a job candidate’s qualifications and character. It can provide clues, both good and bad. A job candidate who drops his head and bites his lip during tough questioning may lack the confidence necessary for the position. Even simple body language such as leaning toward the door is harmful. According to Careerbuilder.com, such behavior suggests you’re uncomfortable with the interview and want out. Knowing body language do’s and dont’s can make for a successful interview.

Dress
Wearing proper business attire that fits helps avoid poor body language caused by wardrobe. Adjusting a tie at the last minute outside a hiring manager’s office could suggest poor preparation. Fidgeting during the interview because of an ill-fitting vest also can detract from the interview. Coffee stains on a white shirt or blouse are not helpful, either, and are a good reason to drink only water before an interview. Simply knowing that a stain is visible can cause the job candidate to engage in defensive body language such as constantly tugging at a suit jacket to hide the problem.

Confidence
Positive body language that shows self-confidence is critical. Hiring managers love take-charge individuals who aren’t afraid of challenges. Candidates with those traits are likely to offer a solid handshake and make eye contact during introductions. Remembering names after introductions is important, too. A job candidate who confuses names during an interview may become flustered and show poor body language that telegraphs the embarrassment.

Posture
A job candidate should maintain good posture even while visiting a company with a business-casual dress code and laid-back work environment. That means keeping both feet on the floor and avoiding slouching in chairs. People already employed by the organization may slouch in their chairs while they work, because they have earned the right to work in their own style. But a job candidate who slouches may appear to lack interest in the position, the interviewer or the subject matter.

Enthusiasm
Good posture allows the job candidate to project the proper level of enthusiasm. Leaning slightly forward in a chair while sitting up straight shows the candidate is paying attention. Nodding affirmatively during key points in a discussion shows that the candidate is engaged in the conversation. On the other hand, a candidate who drums his fingers, rubs the back of his head or stares blankly out a window is possibly suffering from boredom and wants the interview to end.

Practice
Mock interviews with a friend or mentor are often helpful in preparing for interviews. It's ideal if the friend or mentor is a hiring manager or supervisor. The two should dress for the mock interview as if it is the real thing, with a thorough critique after the session.