A business plan is a twenty-five to forty-page written document that describes where a business is heading, how it hopes to achieve its goals and objectives, who is involved in the venture, why its product(s) or service(s) are needed in the marketplace, and what it will take to accomplish the business aims. 

There are three essentials reasons to prepare a business plan: 

1. Entrepreneurs reap benefits from the planning activity itself

2. The plan provides a basis for measuring actual performance against expected performance.

3. The plan acts as a vehicle for communicating to others what it is that the business is trying to accomplish. 

The most common use of business plans by businesses is for funding, to attract/convince investors (and/or venture capitalists), bankers, corporate partners.

I believe business plans fail because:

• you do not take the time to do it right, prepare it for the audience you are going to be presenting the plan to 
• you business plan is static: you do not update it and you don’t really focus on the business environment in which you are operating
• you focus too much on the expected results rather than on the actual results
• there are the wrong people at certain management positions