Noted Harvard Professor of Business, Theodore Levitt, stated that the purpose of all business is to "find and keep customers". Furthermore, the only way you can achieve this objective is to create a competitive advantage.
That is, you must convince buyers (potential customers) that what you have of offer them comes closest to meeting their particular need or want at that point in time.
Hopefully, you will be able to provide this advantage consistently, so that eventually the customer will no longer consider other alternatives and will purchase your product out of habit.