Anyone who is provided with a good, product, service or idea is a customer. Customer is king because he keeps every business afloat. Whether an organization offers a product or service, it cannot remain in business if it cannot find a group of people willing to become its customers. In this tutorial, we will discuss how we can keep every customer – existing or potential – happy and satisfied so that the business flourishes. We will also cover qualities of excellent customer service and different modes of providing it, like in-person, telephone, e-mail, etc.