The marketing plan is the overview of multi_channel approaches you should be implementing to develop and retain your prospects. It may include a call for brand development and demand generation as well. If your existing strategy is somewhat successful, but you want to grow _ the marketing services it recommends may be more focused on customer relations _ such as social media marketing, email marketing and telemarketing services.
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.