Groups of 6: Groups of this rough size are wonderfully conducive to intimacy, high levels of sharing, and discussion through storytelling. The Young Presidents’ Organization, a network for CEO types, has developed a highly structured process that helps peers in groups of 6 thoughtfully coach one another through their problems. Groups of 6 are, on the other hand, not ideal for diversity of viewpoints, and they cannot bear much dead weight. To make the gathering great, there’s more responsibility on each person.

