You may find that the easiest part is the actual writing of the plan. The real work comes in the data-gathering, which may take you a hundred hours or more, depending on what you already know or have researched. If your new venture is in an area where you've been working, you may already know about your customers, your suppliers, your marketing plan, your organizational structure, your financial and cash flow needs, equipment, inventory, and so on.
American Demographics (adage.com/americandemographics): Just as the title suggests, numerous free reports about consumer demographics in the U.S. nationally and by statistical area.
It is a software program that provides step-by-step guidance throughout the process of planning and provides clear instructions and sound advice, along with resources for any additional help that may be required. It provides easily generated financials that are based on an underlying built-in financial model that is integrated with visual forecasting, and financial wizards to fill in the numbers in the pre-designed format of the business template.
But your idea may be so new that you may also need to talk to potential customers, host some focus groups, talk to an ad agency, or maybe even make a prototype and float it past some people. Be prepared to spend the time. Remember, it's not about the Plan but the Planning.