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.
The business plan serves several purposes: Enables the entrepreneur to think through the business in a logical and structured way and to set out the stage in the achievement of the business objectives ; Enables the entrepreneur to plot progress against the plan ; Ensures that the resources needed to carry out the strategy and the times when they are required are both identified ; Preparing the business plan ensures that the entrepreneur has thought through the crucial aspects of the venture ; It is a means for making all employees aware of the business direction ; It is an important document for discussion with prospective investors and lenders of finance ; It links into the derailed, short-term, one-year budget.
What should come into your business plan is how you assess it, how you foresee anything occurring that could have an adverse impact and how you would deal with it in the right ways. If you are looking to obtain funding from a bank or people you know, it is essential to show what the risk factors are in the proposed business and how you plan to defend against them.
Remember the proverbial expression 'not seeing the wood for the trees'? You need to see the 'wood' first, then delve in and start examining the individual 'trees', meaning the individual items which you will be breaking down later. So a great point is to make sure that you have that overarching vision - and if you cannot find one, then maybe it is an indication that you are obsessing on a few technical aspects that do not necessarily make up a whole business as you had imagined it.