You will be interviewed by a panel of around 3 people. One person was kind of the "bad cop" who would ask tough questions, so be prepared for that. The main interviewer will ask you about your professional and educational background, and be sure to highlight any activities that involve cultural exchange or involvment in the Japanese community, rather than strictly interest in Japan. Another interviewer will try asking you questions in Japanese, but this is usually only bonus points for the interview.

There were three interviewers. They asked different kids of questions about my intention and why I wanted to go on the jet program. It wasn't so difficult, but in the end i decided to take a different job somewhere else.

The JET interview process is very easy to prepare for, and there is lots of information online that details precisely the kinds of people they want to hire. If you come across as flexible and at least somewhat outgoing in your interview, I think your chances are good. Normally the interviews are made in a panel of about 3 interviewers.