Location: Writing down the location of your business is very important. Locations with greater customer traffic usually cost more to buy or rent, but they require less spending for advertising to attract customers. This is especially true of retail businesses where traffic count and accessibility are critical. 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.
I have been putting together business plans for over 25 years and it is clear to me that the strength of its core rests solely on being able to execute the plan. Each year I approach business planning as an opportunity, rather than a burden. I would rather invest the time up front in mapping out the upcoming year, than leaving it to chance to dictate my strategy. While this may force me to think strategically as well as tactically, preparing a detailed business plan in advance enables me to identify the challenges in advance of actually facing them.