Don't be afraid to admit you don't know the answer to a question. It's better than faking.
Eat well on the day - no spicy foods!
Remember the importance of body language such as eye contact, posture, active listening and nodding.
Thank the interviewer(s) in person, by email or by post. Common courtesy and politeness goes far in interviewing.
Try not to go off on tangents. Keep your focus on your best qualities.
Ask insightful questions to show you are interested and have done your research.
Research the industry, interviewer, and job role.
Job Hunting Tips:
"The bulk of people unhappy with their job think they can't take time from 'family time' or their energy-sapping job. No matter what the justification, the consequences are exactly the same. Any jobseeking will stutter and you will lose out on critical events."