1) Before you do the interview explain your project to interviewee(s) so that they have some introductory context, can think about the topic before the interview and make sure you get their agreement (consent) for the interview.
2) Put the interviewee at ease. Make eye contact and establish rapport by finding an easier topic to talk about before you get down to the harder questions.
3) Ask open-ended questions. Prepare the questions in advance and don't ask leading questions like "Do you think Franco was bad/good?" Instead ask questions like "What was daily life like during the years of the Franco regime?"
Be prepared to improvise your follow-up questions according to the responses you may get. Practice some possible responses you might expect before the interview and note how you would follow up on each scenario. If your interviewee is shy and gives answers that are too general, calmly dig (ask more questions) for more detail. If you see or hear your interviewee(s) becoming uncomfortable, calmly finish the topic and ask them a different question.
4) Listen more, talk less. The interview is mostly about the interviewee(s), so listen attentively. Pay attention to non-verbal cues such as posture and body language. Ask the interviewee(s) if they want to ask you any questions at the end of the interview.
5) Take notes throughout and record the interview. Take good notes in an organized way so you can easily review them at a later date.
6) Again...understand what you can’t ask. Keep your questions focused on the topics you want to know more about and stay away from potentially upsetting areas if you can see/hear the interviewee(s) getting upset, agitated, angry or nervous. Reassure them if this happens and move on to a different topic straight away.
7) Be kind, courteous and patient at all times. Show compassion. Smile and enjoy this interesting experience!