Plan to arrive early enough that unforeseen delays will not make you late. You don't want a potential employer's initial experience with you to be tainted by you failing to arrive on time. If you are going to be unavoidably delayed, call the interviewer before the time of the scheduled interview to apologize for the inconvenience and ask him or her if it would be more convenient to delay the interview or reschedule it.
Credibility is the most important impression to create during an interview.
This is accomplished by appearing honest, confident, enthusiastic, courteous and inoffensive. Eye contact is the dominant feature in nonverbal communications. The way you meet or avoid someone's gaze can reveal volumes about your character and feelings. Lean forward slightly without slouching Nod affirmatively to show attention and agreement, and to encourage the interviewer to continue talking, but avoid nodding when they say something with which you disagree. Responding To Interview Questions Try to answer every question clearly, accurately, and thoroughly without overexplaining or repeating yourself.