When interviewing for a job, be prepared and learn about the organization beforehand. Prepare answers to broad questions about yourself. Review your resume and practice an interview with a friend or relative. Always arrive before the scheduled time of your interview. Dress appropriately and be well-groomed. Learn the name of you interviewer and greet him or her with a firm handshake. Keep eye contact and try to control any nervous habits like fidgeting or tapping your fingers. Do not chew gum while at an interview; it is very disrespectful.

Source: About.com