When I have received business plans, the very best responses come from people who have looked at the risks and have an answer for every question. What you never want is to throw a scenario at your plan and have to answer "I don't know what I would do in that situation". You want to plan for every possible contingency, and certainly all the major risks to the ongoing success of your business.
Obtain Feedback On Your Plan : When writing a business plan you sometimes end up locking yourself away. You might have unique ideas which lead you to seek some isolation and secrecy, or if you are going to be a sole trader you may only have one person to consult namely yourself. But it is fantastic to try and get broader input on your business plan - whether from a professional, or simply from friends and family whom you trust.
Marketing Plan: Marketing plan lays down the strategies of marketing which can lead to the success of business. These strategies are in terms of marketing mix (product, price, place and promotion). From the market feasibility study and marketing research, potential/ present demands of customers are determined which helps in understanding the profile of customers and hence help in laying down the strategies for segmentation of the market, identification of the target market laying down strategies for target market.
I say that because of course you need to be careful with commercially sensitive ideas, as you do not want to pass your plan on to someone in the pub who then starts your idea before you across the road.