Start the opportunity chapter by describing the problem that you are solving for your customers. What is the primary pain point for them? How are they solving their problems today? Maybe the existing solutions to your customer`s problem are very expensive or cumbersome. For a business with a physical location, perhaps there aren`t any existing solutions within reasonable driving distance.
Investors, lenders, and others know that a market without competitors is typically a tiny and uninteresting market. And, of course, a healthy, growing market will always attract competition. So, unless you`re creating a new industry or a new market segment, you will have competitors. And, you`ll need to figure out how to beat them or at least to compete with them.
There are four main chapters in a business plan—opportunity, execution, company overview, and financial plan. The opportunity chapter of your business plan is where the real meat of your plan lives—it includes information about the problem that you`re solving, your solution, who you plan to sell to, and how your product or service fits into the existing competitive landscape.
Like anything else in business, a business plan should be judged good or bad not in a vacuum but in its business context with its specific business objective. Most of the online discussion about business plans is focused on business plans related to seeking investment, and I`m going to make the assumption in this answer that you are asking about those.
Projections are important not for their actual numbers as much as for their presentation of drivers, relationships between growth and spending, key spending priorities, sales aspirations, and assumptions related to cash flow. They have to be solid and integrated, but accuracy is much more a matter of transparent assumptions than accurately predicting the future.
If you are writing a business plan to get a bank loan or because you`re asking angel investors or venture capitalists for funding, you must include the details of what you need in the executive summary.