Folks, I have been a hiring manager who has conducted hundreds of interviews. Let me give you a couple of tips for a good interview:
1) Show up dressed like you want the job, especially if it is an office-type job.
2) Be neatly groomed, and if possible, find out ahead of time of the employer has grooming and dress codes.
3) Introduce yourself to the interviewer(s) and shake his/her/their hand(s). Use "Mr." and "Ms." when addressing your interviewer.
4) Be polite and succinct in the interview. Think a moment about your answers and speak intelligently.
5) Get the name(s) of the interviewer(s), business cards, if possible.
6) Follow up the interview immediately with a thank you note. You may not get that job, but you will leave a favorable impression. I have called back good interviewees when new positions opened.