Before the job interview
Know the company
Your knowledge of the prospective employer will contribute to the positive image you want to create. Research the company before the interview. Talk to others who work there; ask for information about the firm and for a job description when the interview is set up; use the Internet and your local library’s reference books on public and private organizations.
Know the job
Learn everything you can about the job you're interviewing for and how your previous experience and training qualify you for this position.
Review your resume before the interview to have it fresh in your mind, because it will be fresh in the mind of the person who interviews you. Better yet, have it in front of you on the table.
Prepare questions of your own
Employers are as interested in your questions as they are in your answers. And they'll react favorably if you ask intelligent questions about the position, the company and the industry. (Examples: Where does this position fit into the company as a whole? Is there any problem on this job with waste/accuracy/meeting quotas, etc.? What is the largest single problem facing your staff now?).
Get the big picture
Visualize the entire interview, from start to finish. See yourself as performing with style and confidence. How will the interview end? Will you get a job offer or be called back for a second interview? How much salary do you want? What kind of benefits? The research you do ahead of time will give you an idea of what to expect.
Be ready for any eventuality.