Interview for Management position.

I am interviewing for a promotion to a management role for the helpdesk. I am currently in the team leader position. I am looking for suggestions or advice on how to prepare for this interview. This is not the first time I’ve interviewed for this role and not the first time I’ve interviewed with the person who was also recently promoted to dept supervisor. The person I’m interviewing with considers himself an expert interviewer. The interview is weighed more than past performance or accomplishments.