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.
A successful project report must achieve the following objectives: Be appropriately arranged, with an executive summery, a table of contents and its chapters in correct order ; Be the right length and have the right appearance ; Give a sense of what you and your company expect to accomplish ; Explain in quantitative and qualitative terms, the benefits to the user of your company products and services ; Present hard evidence of the marketability of the products and services.
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.
Describe the manufacturing or operating process and associated costs. Contain believable finical projections, with key data explained and documented.