It needs dedication, follow up and keeping good relationship with the first clients while providing awesome services/products and exceeding their expectations.
Those few clients will bring you more clients if they are satisfied with your services. Patience is all you will need to serve clients because you will definitely work with different people from different walks of life.
You should also ask a client whom you believe is satisfied with your services to write for you a testimonial which you can use to get more clients.
Being in business is providing awesome work for your clients and their satisfaction will move you forward as a business.