Running a business off referrals is the gold standard of having an established name. You do such great work and have such a great product that people share you as a resource! This is when advertising for new customers takes less time and maintaining relationships takes a little more. Referrals is where you want to be in the long run.
When you can run your business on referrals everything becomes easier. People see you as a credible business and are actively passing your name. These referrals indicate that your business is working well within its social networks.
What is a social network? It is a system in which people act and interact on each other. They share information and resources. They defend each other and look out for each other's needs. In essence, they are system of people.
Getting in with the right people makes a difference in your business. If groups of people see you as credible and like what you have to offer they will naturally want to share that resource with others. For example, if you need estate planning then why not go to someone everyone knows?
Get involved in relationships building. That means get involved in your local business community. Join associations, do charity work, connect with people and be seen. The more you can put yourself in front of the right people with your card the better off you will be! Make sure you brush up on your elevator speech because you may only get once chance to sell. :)