What Makes a Strong Magic Playgroup?

Today I wanted to cover the important topic of a Magic playgroup. It is somewhat ironic for me to cover this topic, since for almost all of my time playing Standard Pauper I have been, as Adner put it, a lone wolf. For the most part, I have written articles, built decks, and participated in events without intentionally getting advice from my fellow Standard Pauper players.

Of course, as the newest member of this clan, that has to change.

If you never read Next Level Magic by Patrick Chapin, I would highly recommend it. In this short but tightly-packed book, Chapin covers just about every aspect of mastering Magic the Gathering. Not surprisingly, he has quite a bit to say about the value of establishing a solid playgroup and how that group contributes to the success of all of its members. Rather than trying to regurgitate that section of his book, let me instead give you the highlights.

So what makes for a strong playgroup?

1. Everyone in the group should be actively working to getting better. The best way to improve in Magic is to surround yourself with other people who are trying to improve. Individual success leads to greater success for the group, which in turn supports greater success for each individual.
2. There should be a diversity of skills in the group. Not everyone in the group has to contribute in the same way or even the same amount. But each person should, at the least, be bringing at least one unique aspect to the group.
3. The group shouldn't be too big or too small. If a group has too few members, it risks becoming in-bred, recycling the same ideas over and over. On the other hand, if a group has too many members, it becomes too large to coordinate and communicate effectively.
4. The group should be united around a goal. Everyone in the group needs to understand clearly what the group is trying to accomplish. 
5. The group should playtest regularly and communicate results clearly. At the end of the day, the primary function of a playgroup is playtesting. Play a ton of matches, test out different decks, and communicate with the whole group what is being learned in these playtesting sessions.
6. The group should encourage one another. Magic can be frustrating. Bad luck seems to strike at the worst times. Simple acts of kindness and encouragement go a long way.

So, based on Chapin's work, what do we need to do to make this playgroup as strong as it could be?