The business plan is a necessary but not sufficient condition for finding outside investors. The plan describes the business and what it might become, and that`s all. A beautifully written, edited, and formatted business plan will not make a less investible business more investible.
Later, as the investment process proceeds (if it does), the latest regularly-revised plan will serve as a companion piece to the pitch and a key document for due diligence.
The business plan is an essential component of normal due diligence. Never do a pitch without having a plan, because if investors like the pitch they will ask questions that you can`t answer without a real plan.
This means having the right financial statements, forecasts, and a digestible explanation of your business model available for potential investors. Writing your business plan helps you put all of those pieces together and create connections between them to tell a cohesive story about your business.
Second, your business plan should be a tool you use to run and grow your business. Something you continue to use and refine over time. An excessively long business plan is a huge hassle to revise—you`re almost guaranteed that your plan will be relegated to a desk drawer, never to be seen again.
The executive summary of your business plan introduces your company, explains what you do, and lays out what you`re looking for from your readers. Structurally, it is the first chapter of your business plan. And while it`s the first thing that people will read, I generally advise that you write it last.