The key to improving your social capital isn't the number of contacts you make. What's more important is to develop lasting relationships with your contacts.
Think of how you can deepen your relationships with contacts and improve your social capital.
Perhaps you can give your potential clients a personal call, send them cards, set up appointment for coffee.
Social capital is the international currency of networking, especially business networking.
Start strengthening the relationships within your network which can lead to new business.