If you know little about the war or the social conflicts that surrounded it, you will have difficulty developing good questions, conducting good interviews, and placing oral memoirs into a meaningful context. Your interviews will improve if you are familiar with the chronology, themes, and key figures and issues of the period. Pre-interview reading and discussion will enrich the interviews and improve the overall value of the project. It is also worth taking time to familiarize yourself with interview techniques. Thinking and talking about what makes a good question and a good interview can improve your projects.
Interviews can be short or long.
You should try to find an interview time of at least 45 minutes, scheduled at the interviewee's convenience. If the interview seems to be going longer than 90 minutes or 2 hours, consider stopping and finishing the interview at a second session. Restaurants are generally not good places for interviews, though a calm, quiet restaurant will do in a pinch. Most important is that the person being interviewed feel that they are in a safe place where they can concentrate on the discussion. Then, as the interview develops, your questions can go deeper.