Really deep and rich article backed by research on thinking about networking.

The key is to build a diverse but select network:

The old adage “It’s not what you know, it’s who you know” is true. But it’s more nuanced than that. In spite of what most self-help books say, network size doesn’t usually matter. In fact, we’ve found that individuals who simply know a lot of people are less likely to achieve standout performance, because they’re spread too thin. Political animals with lots of connections to corporate and industry leaders don’t win the day, either. Yes, it’s important to know powerful people, but if they account for too much of your network, your peers and subordinates often perceive you to be overly self-interested, and you may lose support as a result.

The data we’ve collected point to a different model for networking. The executives who consistently rank in the top 20% of their companies in both performance and well-being have diverse but select networks like Deb’s—made up of high-quality relationships with people who come from several different spheres and from up and down the corporate hierarchy. These high performers, we have found, tap into six critical kinds of connections, which enhance their careers and lives in a variety of ways.