Make it clear and concise; include only the most important elements, keeping it at a maximum of half a page. To create the summary go back over your plan, pick three or four key messages and write a brief overview, then conclude with details of the action you want the reader to take.
A business plan is a formal statement of business goals, reasons they are attainable, and plans for reaching them. It may also contain background information about the organization or team attempting to reach those goals.
Your business plan should present what a banker or venture capitalist expects to see, in the order they expect to see it in. Following a standard business plan outline will keep you on track, and save you from botching your best chance at getting your business funded.
The planning process helps you learn about the different forces and factors that may affect your success. If you are already in business, it helps you to step back and look at what is working and what you can improve on. Instead of worrying about the future, a business plan helps to give you a sense of control over your business and your livelihood.