Don't ramble, or talk too much about your personal life. Direct your answer to the job. Also, never bad-mouth your former employer. This is unprofessional and says more about you than about them. Avoid Being Too Familiar.
Familiarity can be a barrier to a professional interview.
Never call anyone by a first name unless you are asked to. Know the name, title, and the pronunciation of the interviewer's name and don't sit down until the interviewer does. Be clear, concise, and direct. Even if the interviewer is easygoing and friendly, remember why you are there. Since nonverbal communication is 90 percent of communication, dressing inappropriately is a barrier that you can avoid.