I have written 400+ business plan in last several years as that is what I do for a living. The approach I have used and recommend for writing a business plan is what I call "Two Sentence Business Plan" and the idea is to be very objective and concise while writing and following a standard framework of answering the what, why, how, when, who, where, of each idea/element and including an action step to it. This will declutter your head, get your ideas and strategy on paper, and guide you in making well informed decisions as well.

The framework is a simple one pager you can see at http://twosentencebusinessplan.com/wp-content/uploads/2014/08/BusinessModel06.pdf however, you can go as complicated as you like by further diving deeper into the granular details that matter most to your business.

I'd happy to help you with details specific to you and your business, over a call, if you need. Cheers!