Everyone needs a good role model to look up to. Most times in needs to be someone outside the family because kids lose confidence in their own immediate family and feel they are closed minded and shallow. Having an outside influence they can talk to and relate to does help.
the biggest impediment to successful mentoring is overzealousness. you have to be calm, levelheaded and take things in stride. if you seem overly interested they will think your just using them as a case study. be friends with them on a personal level, don’t make it seem like a therapist-client relationship.