How to have a successful interview (2)

Remain respectful, professional and confident, smiling a little (not with a pasted on grin) and be as calm, yet enthusiastic as possible. Don't act nervous, tapping fingers, wagging your legs or wringing your hands (crossing ankles or arms is considered defensive/in a standoff), nor sitting stiffly as a statue, but also not flopping around like you're lazy (silly or too relaxed). If you're asked to answer a case (what if...) question, talk through the process you would use, in such a case.
Don't be afraid to ask whether your ideas sound thorough enough—you'll be evaluated on your ability to structure your thinking and to share your thoughts well, not on the number of questions you ask. In fact, talking through your process is a great way to engage the interviewer and turn the interview into more of a give and take discussion. This can give you valuable clues and a guide on what they want to know (so you can show how you can fulfill their needs).

• If you need something clarified, don't be afraid to ask. You'll do better, if you know exactly what is being asked of you. Don't ask a question every few seconds, or you'll sound confused (you want to show that you have good motivation toward what's good, reasonable and logical).

Sell yourself. What are your unique selling points and how can you match your highlights to what they want? Make sure you use plenty of examples as proof of your abilities. Show the interviewer that you can find the positives in your past experiences—this is not a time to complain (and shoot yourself in the foot) about what you hated in your previous work situation(s). Focus on how this really is good/much more suitable to you.

• Remember those examples of your strengths that you wrote down earlier? This is exactly when they'll come in handy.
• There's a difference between being confident and bragging. Make sure you show what a capable, intelligent employee you are without singing your own praises.

Be inquisitive. Don't forget to ask your questions. Pay attention as the interviewer answers—you may even want to jot down notes. This is both to prove that you are listening and also to give yourself a way to reflect on the interview later, if you end up having to decide between multiple positions.

• Don't ask the same questions at every interview. Ask questions that are tailored to the company to show that you've really done your research.

Be polite. Listen to each question fully before you begin to respond. Never assume that your interviewer has read your CV, but don't treat him or her as though he or she hasn't, either. After the interview, do not forget to send a follow up thank you-email. These are generally better than hand written thank you notes, as they are quicker than snail mail. However, you should be sure that it is well proofread and addressed to the right person and identifying yourself and the matters involved, before you send them.

• Part of being polite is remembering to thank the interviewer for meeting with you after the interview. Show him that you really appreciate the time and effort he spent on speaking with you.

Be persistent. Keep interviewing. The more you interview, the better you will become at it. Don't get discouraged. It's unlikely that your first interview will lead to you landing your dream job, but that doesn't mean you should lower your standards after the third interview. Keep aiming for what is realistic for your goals and background, and you will eventually find what you're looking for.
(culled from wikihow)