When you sit down to compile all of the elements of your business plan, make sure you have each section able to stand on its own merits. This means you should not reference other sections sending the reader (your potential investor) back and forth between sections.
For an online business, a detailed and in depth business plan is usually not necessary unless you are trying to combine your online business with a traditional business. For most online business startups, the detail involved with planning a traditional business is not required. However, it would still be beneficial to you if most of the topics were still covered, even if only briefly. Having a written plan in front of you will help you to focus on important aspects of the business.
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.
This part of the plan details the features and benefits of your products and services, their seasonality and life cycle, as well as any future products and services you are planning. It also includes a thorough market analysis, in which you will study your customers, your competition and the market itself. Here you should include a PEST analysis, in which you will consider the impact of various factors upon your business. The factors include combinations of the following, depending upon your business: social, technological, economic, environmental, political, legal, ethical, and demographic.