At some time in all our lives, we are called upon to interview someone else. To find out what they know or don't know, be it for our own knowledge or someone else's. Some basic tips will help you find out what you want and need to know about someone in a way that is effective, cordial and without the use of truth serum and torture racks.
Pick a place which is comfortable for you, and for the interviewee, if you do not have such a place already. Do not pick a place or situation where food is involved, though offering and imbibing a drink of coffee or tea (not booze) would work.
Think about what you want to find out from the interviewee. Make a list of specific things you want and need to know about them for your purposes or purposes of the person who is hiring you to interview them. Let the interviewee do most of the talking, and note if he/she stays on topic. Do not let him or her make you do most of the talking, and get off topic.
Speak directly and from the hip, without the standard "what do you see yourself doing in five years" lines. Invite the interviewee to present him/herself openly, even if it involves telling the interviewee something about you first that is "personal" or "from the inside." Before the interview is over, be sure that all of your questions are asked. Note body language as well as what is said. Also, note what you are projecting to the interviewee, and be sure that you aren't telling him/her what is "right" to say.
End the interview cordially, without giving false hopes to the interviewee. Remember that he/she is (or should be) interviewing you while you are interviewing him/her.
Honesty is something that is intrinsic to our better nature but something which we have been trained to not use. It is your best tool. Remember that though interviewee may not suit your needs now, but he/she may serve your needs and wants in the future.
You will never see eye to eye on everything with anybody. Don't expect or demand to do so.