1. Most important. Always be positive. If you are asked a question like "What are you weaknesses?" answer with something like "I don't see myself as having any weaknesses just skills that can be further developed while working for this company". It shows positivity about yourself and that your keen to work for the company.
2. Never ever ever ever ask about how much money you will get, and if asked about money say "We can certainly discuss that a later stage when I am successful", this shows your are more interested in working for the company than money, and again more positivity about yourself.
3. Try not to fidget, try not to look down at the floor, and even if it feels weird try to keep eye contact for as long as you can, and look at who you are talking to, it may be more than 1 person interviewing you (most hospital interviews are like this 2 or 3 people - one focussing on questions, one checking your mannerisms). And never sit down on your own, always wait to be asked to sit, and never sit with legs crossed.
4. Cleanliness is a major issue, be neat and tidy, don't go in with designer stubble on your face. Haircut's are always good too. This shows you make an effort to present yourself very well for not only the company but you too, you take pride. This will go over well as the interviewer may look at this as you are a person who takes pride not just in appearance but in work too.
5. Study the history of the employer (not full history if its a multi-century company) but enough key points that you could introduce during your questioning. The interviewer may ask you "What do you know about us?", then answer them with key points, like year founded, recent growth, etc.. this shows your interest in the company also and also shows you know how to prepare yourself.
6. Keep slang out of your speech, calling the interviewer buddy or mate is a sure fire way of not getting the job.
7. When arriving and leaving always give a firm handshake and look into the eyes of the person you shake hands with. And try to leave on this note.. "I look forward to hearing from you soon" (don't say very soon thats kinda pushy) and dont forget to thank them for their time to interview you.
EDIT: Some extra stuff.
8. Plan your travel accordingly, do a test run to the place of work so you know you will be there on time and it is easy to get to.
9. If you feel you are going to be late, DO call the employer and let them know, nothing worse than saying nothing and letting an employer wait and think you have horrible time keeping
[Edited by DABhand, 11/24/2010 4:04:38 PM]
[Edited by DABhand, 11/24/2010 4:05:58 PM]