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.
The expected revenues and expenses for at least a year should be projected in the cash flow section of the Financial Plan. It's better to make conservative predictions rather than be too optimistic when it comes to cash flows. As part of this section, a break_even analysis is essential. This is the "amount of units sold or sales dollars necessary to recover all expenses associated with generating these sales." (NxLevel for Entrepreneurs, 2005) The formula for calculating the break_even quantity is Total Fixed Costs/(Price _ Average Variable Costs).
Who should prepare the plan? _ As a business consultant, this may sound like heresy, but I believe that any plan should be produced by the senior management of the organisation. That is not to say that the consultant does not have a role to play in its preparation. He does. Senior management should prepare the plan as they will then be able to present and discuss it, demonstrating to their audience that they fully understand their business and market. I believe that the consultant's role is to help facilitate the preparation of the plan, the consultant can help undertake the necessary research, and can cast a critical and impartial eye over the plan.