Marketing is your most important organizing tool. There are six basic aspects of marketing, called the "6 P's":
Product: The quality and uniqueness of item or service you sell.
Price: The amount you charge for your product or service.
Promotion: The ways you inform your market as to who, what and where you are.
Place: The location and distribution of your product or service.
Packaging: The way the business looks from the promotional materials to the dress of the staff.
Personnel: The level of customer service you give.
As you can see, marketing encompasses much more than just advertising or selling. For example, a major part of marketing involves researching your customers: What do they want? What can they afford? What do they think? Your understanding and application of the answers to such questions plays major role in the success or failure of your business.
Erik Bowman has been to exactly where you want to go and has written brilliantly about how you can get there yourself. His books on start-ups give you a head start and a major competitive advantage. - Jay Conrad Levinson, The Father of Guerrilla Marketing