While these are easily available online, some of them are way better than the others. A lot depends on the approach that goes into writing the business plan.
Risk Assessment - What weaknesses are inherent in this venture? What vulnerabilities face this type of venture? What impact will these have? What new technologies may affect this venture over the next 1 to 3 years? What contingency plans are in place? What level of liability insurance is required? What does it cost? Who is the carrier? Possible Data Sources: trade associations; trade journals; Service Corps of Retired Executives (SCORE); industry salespeople; customers; focus groups.
Not surprisingly all these individuals have been in the business game for a long period and understand what they're speaking about. While you are in the beginning stages which may be just what exactly you will want, a professional available to assist you to on your way.
Besides, your friends may be 100% behind you in your new venture, but, in case you are hoping to involve others who have actual money to invest, you may need to be able to make a convincing case. Wouldn't it be nice to have anticipated possible questions and be ready with plausible answers? If you are risking your own money, that is perhaps even a stronger reason to do some indispensable planning.