“Repeat clients” may not be in the nature of your business. For example, you may provide a service that clients only need once or once in a while. Rather, your “regulars” might be another group of people like those that your partner up with on particular jobs.
Usually a client becomes a repeat client when you have delighted them or it is really easy to do business with you. If you have an easy, transaction-oriented type of business (say printing business cards or providing a personal service), repeat clients are the key to success.
My experience with repeat clients is that a vendor needs to make it really easy to do business with them.They need to be consistent, honest and friendly. Why do we go to McDonald's over and over again? Because we know what to expect every time. In order to get repeat client(s) become a known quantity.