The steps involved in preparing for a requirements interview are just as important (perhaps even more important) as the act of conducting the requirements interview itself. The quality of the requirements obtained during the interview is closely dependent upon the preparation done upfront.  The business analyst should:

1. Identify the interviewees based on their knowledge and their authority to provide the necessary requirements.
2. Schedule a time and place to meet and conduct the interview.  20-30 minutes is all that should be needed if the analyst has properly prepared.  A quiet conference room or office works best.
3. Develop a balanced list of 7-10 high level open and closed ended questions that will be asked.  Consider creating a few follow-up questions for each that may be asked based on the answers the interviewee gives. Keep the follow up questions on a separate list, these will not be provided to the interviewee.
4. Sequence the questions to ask about the as-is process first.  The list of questions should start with higher level questions and then drill down.
5. Send the primary list of 7-10 questions to the interviewee several days ahead of time.
6. Confirm that the questions were received.
7. Follow up with the interviewee shortly before the interview to remind them that you will be meeting to discuss the questions forwarded earlier.  This allows them to quickly prepare before the interview since most won’t have taken the time to look at the material.