The only genuinely bad interview I have had was for an internal job which would have taken me from head of maths to senior teacher. I felt that when I came out I hadn't said what I had wanted to say, and that I hadn't been coherent in my views.Because I knew everybody and had been in the school a long time, I probably didn't prepare properly. Consequently, I didn't get the post.
But in the end it did my career a power of good. It made me focus on what I really wanted - whether I wanted to continue in that school and whether I genuinely wanted to be promoted.
Just after the interview, somebody told me it may have been the best thing that had happened to me. In those days, senior teachers were relatively new in schools, and most people had gone from head of department or senior classroom manager, straight to deputy. This new job had come in, and tended to slow down your career path. A little while afterwards I did a masters in education and eventually I did get a deputy headship - and moved on.
People sometimes give too little thought to preparing for interviews and too little time thinking what's going to be said or how they're going to be questioned. I also learned that I wanted people to be relaxed in an interview, to feel comfortable about saying what they really wanted to say, not what I wanted to hear.
The best interview was one of the shortest interviews I ever did. I remember going for one deputy headship interview that lasted no more than 15 minutes, but I felt that when I'd left I'd said everything that I had wanted to say. I was to the point, I didn't waste any words in my answers, I said exactly what I wanted to say. I got the feeling that if my interviewee didn't agree with what I wanted or didn't fit in, it was best for both of us that I wasn't appointed here.
Some interviewees make life easy for you - they don't put you on the spot with any of their questions.
Good interviews that I have sat in on have also not usually been long ones. People need to realise that when you're listening to someone, if they don't get the crux of what they want to say over quickly, then the rest is mostly irrelevant.
John Howells is head of the Leasowes Community College, Halesowen, West Midlands. Interview by Martin Whittaker