Let me first admit that I am not experienced business consultant but I volunteering on this site and one of the first suggestions I see other Mentors giving is, "Write a Business Plan..."
No offense but there are a few things that should be identified first.
Background. I have started, and sold, Two other small businesses, one which was fully established and not quite making a profit when I sold it and the other was fully established and doing USD$4,000,000 a year in volume with a nice profit after about eight years in business (started in a new city from scratch). I have also started, and still own, several other small businesses, the major one doing in excess of USD$10 million (I wont say how much) and the others are doing just fine.
Never went to college but I read self improvement, philosophy, psychology, history and other books all the time.
After seeing multiple "mentors" suggesting a business plan I spent a few minutes online looking to learn what one was. Whew! If you are a one/two man show, just starting out, looks like a huge waste of time to me. Sure, if you want to do it, go ahead, and you will probably learn something but here is my "abbreviated" and introductory version of a business plan.
What is it you want to sell?
Is there demand for it?
How do you KNOW there is a demand?
How will you be different from everyone else who may already be doing this?
Numbers 3 and 4 should be very, very detailed. Especially number 4.
I only thought about the above four points for a minute but these four questions will get you most of the way down the road and you should be able to show it to several other small business owners, who are already successful, and they should clearly see whether or not you should continue with your idea or business plan.
If you cannot answer 2, 3 and 4 you are already in trouble.
But answer them fully and show the results to several people who should know and if they say "Yes!" you are on your way.
That said, even if I did this and someone, who should know, said, "No way you should do this..." I probably would have anyway but I would keep rewriting the above three questions until I had something that made sense.