My experience over the years is that when managing a team, selecting the right members is much less important than creating the right conditions so they can work. In volunteer projects, we often have no control over the participants. What a relief to find that how people are allowed to behave matters more than anything they bring to the table.
Only Dead Fish: On High Performance Teams, 2016-Mar-5 by Neil Perkin
This lengthy New York Times piece on the lessons that Google has learned from its lengthy quest to find out what makes an exceptional team [found...]
Team composition, longevity, degree of hierarchy, and the mix of personality, background, skills of the team members all made no difference.
Instead, further research revealed that the group norms ('the traditions, behavioural standards and unwritten rules that govern how we function when we gather') that the team operated to seemed to play an important role in how successful a team was. Analysis of over a hundred groups for more than a year showed that the right norms could raise a group’s collective intelligence, and the wrong ones have the opposite effect (even when individual intelligence was high).