It may not be pleasant to imagine all the "what ifs," but doing it now and planning for those unexpected events will improve your company's chances of surviving a storm. For an excellent step_by_step guide on the details of developing a risk management plan, see the article "How to Develop a Risk Management Plan," by Charles Tremper at wikiHow.com.
If an online business, you need to go into detail how you will attract customers to your website. General statements like "I will use Face Book ads and email marketing" will contribute almost nothing to helping your cause unless you have detailed statistical analysis of tests you have conducted or of another similar business you have been associated with. If you do not have any data upon which you reference your estimates, it could show lack of proper thought to the remainder of your business plan.
The organizational section of the business plan also needs to include an explanation of your record keeping process, checks and balances, and control management systems. Anyone who reads your business plan should be able to understand the organizational procedures for running your business day_to_day, as well as in an emergency situation.
Describe your most important company strengths and core competencies. What factors will make the company succeed? What do you think your major competitive strengths will be? What background, experience, skills, and strengths do you personally bring to this new venture?