Identify your audience. A good business plan should be written from the prospective of the audience. First, you need to decide on the purpose the plan. Are you trying to persuade an investor to take on your project or communicate the future plans for the company? The purpose of the business plan will affect the style and content so make sure you are clear on this before beginning. A good business plan needs to be tailored to the specific requirements of the target audience in order to be engaging.
A brief account of how the company began- You should mention in your business plan the history behind the formation of you company and the background of the founders and directors.
External stake-holders of non-profits include donors and the clients of the non-profit's services. For government agencies, external stakeholders include tax-payers, higher-level government agencies, and international lending bodies such as the International Monetary Fund, the World Bank, various economic agencies of the United Nations, and development banks.
Once you have done all this you should have a complete and detailed professional business plan. The most important thing to remember when developing the plan is to see it as a living document and include specifics regarding dates and specific responsibilities. Your plan will need constant reviews and updates and things change so expect it to be a work in process for a good stretch of time. It will all be worth it in the end, a well-written plan will help ensure that the business is fully focused on what is required to achieve the company's goal.