Marketing is the process of selecting your desired customers, defining your service offering, presenting your service offering to the desired customer group, and communicating your offering in a manner that reaches your audience and generates actions that result in the desired transactions.
Every business selects their customers by the offering that they present and how it is presented. Some businesses select their customers purposely, and others select their customers by default. In return, customers make their decisions by selecting the services that meet their needs. All that they have to rely upon to make their decisions is the information that the business puts forth, combined with information shared by other customers or people familiar with the business.
If you want to take charge of your business, take the time to define your service offering. Previous discussions of Segementation, Targeting, and Positioning will be helpful. Define your services, select your customers, and communicate your offering to them repeatedly.