In essence your CV/resume and/or application letter are designed to get you into an interview. They may be so good that they have pretty much decided to give you the job but in most circumstances this is where you really have to sell yourself and, lets be honest, if it is nearly already in the bag then this could also be where you throw it all away.
1. Preparation
a) Get some practice interviews under your belt.
b) Print off your resume/CV and make sure you learn your 'personal profile' statement as this can answer a range of questions they thro at you: "Why do you think you should get the job?". "What do you bring to the job that someone else might not".
c) Sketch out 2-4 questions to ask at the end. These shouldn't be about pay and holidays (they can wait until after you are offered the job when you can start the discussion) but should be more positive questions aimed at showing you are interested in the job and the firm: "What are the plans for expansion in the future?". "What is the situation for in-work-training?", "What are the promotion prospects?", etc.
d) Research the company - you should have done this for the application letter but it can't hurt to check again. SMEs may also have pictures of the staff on their web site and it can help to be able recognise the person interviewing you.
e) Make sure you have an answer to the killer question: "What are your weaknesses?". Try to make them as positive and job focused as possible e.g. "I work too hard", "I am too tenacious", "I have trouble 'switching off' in the evening and often find myself reading web deisgn books", etc.
2. Body language/psychology
Here is where they can assess what is really happening behind your interviewing 'facade' and you can also
a) Don't invade their space - wait to ask to sit down, don't spread your things out on their desk or pile you coats and bags up (think about leaving them in reception), etc.
b) Adopt a relaxed and open stance but keep it formal - lean forward slightly, maintain eye contact and don't cross your arms our slouch.
c) Never be afraid to ask for clarification - at the very least it show you are listening.
d) Unless you are a method actor, psychopath or are just damn good at it - don't lie you will be giving out all types of signals. It is worth rembering this when you compile your CV/resume and application letter - if you lie there (or massively exagerate the truth) then it is the interview where you will be caught out.
e) Remember the most nervous person in the room is probably the person interviewing you - at the end of the interview the worst that can happen is that you are still in the same position that you wer ein when you walked in the door. However, the person recruiting you has to make sure they get a good person for the job and they could potentially get sacked over a serious error. They may also be badly prepared or lacking in experience (esp. in smaller companies) and you may have to be prepared to step in an lead the interviewer if they dry up - in this case general questions about the company and the job should give you enough information to keep going and telling them about why you are good for the job.
3. Don't:
a) Swear
b) Smoke
c) Criticise you former employers.
d) Say 'no' - agree to everything they ask you to do. They may be testing you and even if they aren't those things (like "will you make the tea for everyone?") are opening to negotiation after they have offered you the job.
