Describe the manufacturing or operating process and associated costs. Contain believable finical projections, with key data explained and documented.
Preparing a Business Plan: A business plan has to be in accordance with the organization in question, its situation and time. However, a business plan is not just a document to be produced and filed. Instead, business planning is a continuous process. The business plan has to be a living document, constantly in use of monitor, control and guide the progress of a business.
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.
It could be, for example, the risk of a change in the economic environment - what are your contingency plans for that in terms of dealing with such a situation? There may be many other risks as well specific to your particular sphere of operation, but that ability to plan ahead for all scenarios makes for a robust business plan.