In principle, big ideas are always the result of putting our heads together. Really big ideas are already out there in the heads of many people, just waiting to be put together. Without sharing my ideas among fellows and without openness to new ideas, I am a prisoner of my own limitations incapable of more than I can imagine.
Practical Tip: The group is best served when participants are humble. You probably do not have all the best answers, and if you do, it is surely a small matter. Talk with others about your ideas and their ideas. Release your ideas, let them be criticized, and let them be built upon. Trust the wisdom of the group. It is okay to not understand everything; that it does not all fit in your head. Be open to ideas and achievements beyond your imagination.