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.
A plan should include but is not limited to the following: 1. A statement of your business purpose 2. A description of your company 3. The goals of your company 4. The structure of the company (sole_proprietorship, partnership or corporation) 5. The product or service that you are selling 6. A market analysis of your product or service 7. Resources spent (time and money) 8. A financial plan to include financial statements 9. Information about the managing principals in the company 10. How you plan to manage and operate the company