Jeff Sutherland has recently done a great job in describing his ideas on scaling.
Here are a couple of things I think are key:
1. Scale down. That is, it is complex to get lots of people involved in one problem or effort. Simplify.
2. Use patterns.
3. There are alternatives. While there are some common patterns, and they can work, do not assume every pattern will fit your situation. Be judicious and experimental. Expect experiments may not work out well (for a variety of reasons, including ineffective execution).
Here are the modules. They include video and slides. See both.