Business Description: After the executive summary, you need to write a short description of the business you are going into. You need to give a general description of the industry your business belongs to. You will write about your company's mission statement, goals and objectives, business philosophy, as well as its legal form of ownership (sole proprietor, corporation, LLC, etc.).
The three basic actions for growing a business in any economic climate are: improve efficiency (maintain output while reducing inputs, such as time and money); increase volume (produce more in order to spread fixed costs); reorganize the business (change goals, methods and/or philosophy). If you plan to implement one of these, you may as well plan to implement them all. By focusing on one of the above strategies, you will find a ripple effect that causes a need to address the others. This is a good thing.
Financial Plan _ The financial plan consists of four sections: Financial Worksheets, Cash Flow Projections, Financial Statements, and Additional Financial Information. All of these components will tell the story of how you plan to start or grow your business from a financial perspective. It is vital that you explain the assumptions under which you have based your projections, for example, "We assume that there are no unforeseen changes in economic policy to make our products and service immediately obsolete." or "We assume interest rates will stay the same over the next three years." (both quotes from Bplans.com sample business plans)
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.