Therefore, I would ask the candidate to describe how he/she has acted to achieve that. After the interview, try to find out if the stories told during the interview can be verified. It is not uncommon that people lie during job interviews.
In addition to asking your prepared questions, listen carefully and observe the interviewee's behavior in general. Build an explicit impression of the candidate in your mind during the interview, and formulate a smart question or two based on this. These improvised questions might turn out to be the ones leading to the most revealing responses.
In general, carefully observe the behavior and responses throughout the interview. Does the interveiwee indicate any kinds of character weaknesses? E.g. people who feel threatened and unsecure generally make bad managers.
Good luck with the interviews!