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.
I have written business plans for all manner of industries: a coin operated jukebox company, airlines, travel companies, new product launches, and anti_aging product companies. It is not necessary to have a passion for the product or the company to write or develop a business plan. What you must have is a passion for aggregating information, getting involved with and understanding the service or product, and understanding the financials of the product or service. By financials I am not referring to having a CPA before you undertake the task, but rather understanding the presentation of the information and analysis/ numbers to support the activity being planned. Financials are important because they are the score card in the world of commerce.