If an online business, you need to go into detail how you will attract customers to your website. General statements 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.
As importantly, it also identifies road blocks - in advance. Your business plan should provide a common vision supported by tactical initiatives that, ultimately, creates greater value for your company. It may seem daunting, but by knowing your vision and its corresponding financial targets, you will have a better chance at executing how to get there and avoiding traps in advance.