I continue to get good traction from the distinction of our 3 circles. Our first circle includes people we know well - we and they have a "relationship." Our second circle includes people we know of, but don't have a relationship with. Our second circle people are usually our first circle's first circle. Third circle people are those we don't even know exist, yet we are nonetheless connected to in 2 steps - we know someone (in our first circle) who knows someone (in our second circle) who know them (in our third circle).
Increasing the scope of new knowledge, ideas, or resources can happen in at least 3 ways:
1. Interacting more with first circle people who we only interact with infrequently
2. Interacting more with people in our second circle
3. Interacting more with people in our third circle