Start by writing a description of your business, including what stage of development it is currently in (conception, start_up, first year, mature, exit) and your plans for growth. Discuss the nature of your business, the main products and services you offer, the market for your products and services, and how and by whom the business is operated.
Competitive Analysis: Business by nature is competitive, and few businesses are completely new. If there are no competitors, be careful; there may be no market for your products. Expand your concept of competition. If you plan to open the first roller skating rink in town, your competition will include movie theaters, malls, bowling alleys, etc.
If an online business, you need to go into detail how you will attract customers to your website. General statements like "I will use Face Book ads and email marketing" will contribute almost nothing to helping your cause unless you have detailed statistical analysis of tests you have conducted or of another similar business you have been associated with. If you do not have any data upon which you reference your estimates, it could show lack of proper thought to the remainder of your business plan.
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.).