A successful business is raised on the foundation of a great marketing plan. Selling is the most crucial and also the most difficult aspect of any business. Marketing of a product or service is real hard work and a good marketing plan is what ensures that the hard work bears fruit. It outlines how a business will go about attracting prospects, converting them into customers and retaining these customers in the long run.
What was the outcome? As much as 90% businesses started by entrepreneurs and small business went busted or failed within a year. I experienced one of the many busts few years ago (with my cafe business) because i don't really have a proper and "the few solid sheets" called a marketing plan.