Do not try to write your business plan in one sitting. As I mentioned in the beginning, for a traditional brick and mortar business, it could take in excess of 100 hours to compile all of the information needed into a comprehensive but yet understandable document. For online businesses, probably not that long. But your final product should be well thought out, well documented and easily understandable.
Start by writing a description of your business, including what stage of development it is currently in (conception, start_up, first year, mature, exit) and your plans for growth. Discuss the nature of your business, the main products and services you offer, the market for your products and services, and how and by whom the business is operated.
A recession is the optimal time to reinvent competitive advantage because the pressure of a feeble economy will separate the strong businesses from the weak ones, with the weak falling out of the game entirely. Your business will be strong if you have a plan of action based upon a little industry research, an analysis of what you have and what you want, and continuous monitoring of the results of your plan. This kind of innovation is not only a necessity right now, but it is an opportunity to improve the quality and efficiency in the way you do business.
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.