You must know your competition in and out. Keep your friends close, but keep your competitors closer. You need to know all the things that you learned about your customers except fill in the blank for each competitor on all of those above items. Learn how you are the same/ different. Learn the similarities/differences about each product and service you offer. Learn how they sell or promote their products /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.