The most important thing you must do to prepare for an interview is to study the company in advance. By going to the interview prepared and able to demonstrate understanding of the company’s business, you will show that you are actively interested, rather than simply seeking any job anywhere. This gives you a critical advantage.
Remember that big public institutions and recruitment processes in general can be bureaucratic and slow. Some organisations use recruitment agencies, which might either speed up or slow down the process. One can easily lose courage along the way.
Who are the key people? The recruitment manager within the organisation, and of course your potential manager.
Research the interviewers. If you are interviewed by a person who is listed on the internet, find out as much as you can about him and his work. Save your energy for the key people if having many interviews at the same time. It could be fatal to burn off your precious energy with human resources or a recruitment agent, and then be tired for the most important interview with your potential manager.
If possible, find out the format of the interview process beforehand. You should avoid contacting the interviewers directly to ask process questions, but you may be able to find out by contacting the HR department or recruitment agency with a polite e-mail or phone call. Perhaps you know someone who has already been interviewed and can ask them. Finding out this can make your interview a much more relaxed:
Think about questions you'd like to ask about the specific job you have applied for, and also about the company in general. Take a written list of questions with you. This is also your opportunity to show you are serious, and demonstrate your understanding of the organisation.
Ideas of questions to ask your interviewer:
Although you've thought about the salary side of things, always allow your interviewer to initiate these discussions. This might not occur during the first interview. Negotiate as late as possible: you will have most influence when the recruiter already wants you.
During this preparation, don't forget that you may not be quite right for one job, but perfect for another. Don't be afraid to cancel the interview if you discover that the company doesn’t have a culture that suits you for example.
Companies differ. One person's dynamic and exciting environment may seem competitive and back-biting to another. It's your opinion that matters. A company's literature and also your interviewer will provide clues on how to convey the impression that you'll fit in. But bear in mind that before accepting a position you must believe that you really will fit in. If the organisation's culture is very different from your own, it's unlikely you'll be successful.