Dressed to impress
Dress in any appropriate outfit that mirrors their professionalism. Just remember to keep it simple, but elegant--Men in business suits, or shirt and slacks; women in pant suit or blouse and knee-length skirts or long pants.
Mind the time
Avoid planning for an interview during your lunch breaks or during any short breaks in between in order not to rush over things. You may get all panicky and lose your focus should you need to dash here and there for the interview.
Be careful of what your body language speaks
Greet the interviewer with a strong, firm handshake as a start. Don't hunch and remember to look at the interviewer in the eyes. These small gestures leave a lot of obvious clues to the interviewer about you and your confidence.
Give me some energy!
Leave your monotonous speech behind and insert some energy and life into your words and expressions. Speak clearly and loud enough while answering all questions enthusiastically.
Behave professionally
You may find yourself striking up the right cords with the interviewer but always remember to keep your conversation professional. Just be pleasant throughout the interview.
Good riddance to all negativity
Keep your grudges with your ex-boss at bay and be careful with your answers. Do not condemn anything related to your current or previous management or company. Your answer will reflect your maturity and as someone who keeps hatred in mind.
Do your research
Run a search through the Internet on the company hiring to get some basic company background knowledge. Never pretend to know the answer to some questions posed if in fact you really don't.
Send a thank you note
Send your interviewers a short thank you note to carve a lasting impression of yourself. The thank you note may just prove to be your entry ticket to a second interview or even a job offer.