It is usually recommended that these projected statements be on a monthly basis for at least the first twelve months or until the business is projected to be profitable and stable. Activity displayed beyond the monthly detail may be in summary form (such as quarterly or annually). The forecast period for most business plans is two to four years.
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.
I suggest that you construct easy to read tables and graphs for the financial portion of the plan. The worksheets suggested are: Salaries/Wages and Benefits, Outside Services, Insurance, Advertising Budget, Occupancy Expense, Sales Forecasts, Cost of Projected Product Units, Fixed Assets, Growth (or Start_Up) Expenses, and Miscellaneous Expenses. You may find some of the worksheet templates at PlanWare.org to be useful.
Studying your market will give you insight as to how you can make your business more appealing to people. Market research is more than just noticing trends in your customers' buying habits; it's discovering what motivates your customer to buy. Don't assume that you already know because you've been in this business for years. This study often unearths characteristics about your market that are hidden or new. It's best to discover these things before your competition.