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.
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.
The three basic actions for growing a business in any economic climate are: improve efficiency (maintain output while reducing inputs, such as time and money); increase volume (produce more in order to spread fixed costs); reorganize the business (change goals, methods and/or philosophy). If you plan to implement one of these, you may as well plan to implement them all. By focusing on one of the above strategies, you will find a ripple effect that causes a need to address the others. This is a good thing.