I stumbled across a web site for job seekers the other day. The author was selling an ebook on interviewing. His compelling sales pitch was "I know what questions you'll face, and I can tell you the perfect answers." It got me thinking.
The premise is flawed. There are different types of interviews, and the agenda for each is significantly different. So are the questions you'll face, and the right answers. Furthermore, there are no stock "perfect answers." They will always be contextual, based on your qualifications and what that particular interviewer wants to hear.
Having said that, here are basic types of interviews/interviewers, and a few notes about each:
Human Resources. This interviewer may have no technical knowledge of your field. Their job is to try to look out for candidates who don't match the company culture, who have "employability" issues like unacceptable employment gaps or who say negative things about past employers.
Your potential manager. This person will typically have a better technical grasp of your field, or will at least be much more concerned about your knowledge, experience, etc. He or she will also be evaluating how well you stack up against the things they want to see in a subordinate -- innovation, attention to detail, work ethic, communication skills, etc.
Peer/colleague. Many companies will have you meet the people you would work with. Unlike the others, this group may come closest to evaluating you as they might a potential friend -- do they like you? Hopefully they will also be concerned with how well you can do the job (so they won't have to do your work for you).
Granted, this is an oversimplified picture. Not everyone who fits into these categories will correspond to the generalizations I've made. That's exactly the point, though: there are no stock answers to interview questions. The challenge you face is to size up each interviewer, guess what their agenda is, and adapt accordingly.