For distant relatives you may not know well, you may have to gain their trust before they'll open up.
Begin by sharing information about yourself and your genealogy research.
Plan to do a series of short interviews. As you become more familiar with each visit, the more your relative will open up. You could theme these interviews ie schooldays, family holidays, daily life at home, wartime experiences etc. Finding family stories in this way may be beneficial if you are planning to write-up your ancestral trail at a later date.
You'll get the best from your interview if you do it face to face. Unfortunately, this isn't always practical.
Next best for this type of research interviewing is the telephone. Follow these tips:
Part I - Family history interview - preparation