That said, there are a few keys to developing a good business plan, the first of which is making sure you have a product or service that people actually want to buy, rather than a product or service that you think they want to buy.
This is the first flaw for most would-be (and sometimes even seasoned) entrepreneurs, and can be avoided by some good up-front due diligence by going out to your prospective customers and getting their feedback on your product or service.
You can also generally gauge potential revenues by looking at your proposed price points and extrapolating those over percentages of population segments in your selected metropolitan target areas, based on your competition and what they are doing. This will also tell you if your idea is viable, and if the market is indeed big enough to go after.
An example of a market that wouldn't be a good market is a local area with five transmission shops and you want to be number six. If the total revenue for that area is say $5 million, that means that the top two shops probably have 80 percent of the market, and the other stores are struggling. Even the top two might be struggling, depending on their expenses.
To break into this market, you would have to capture the majority of market and wallet share, while keeping your expenses to the bone. While you might say, "I can do it," the numbers will be against you and in reality you should just move on to another idea.
Take a good look at the numbers, because a bank or any investor will. If the numbers work, you'll get your investment. If they don't, move on. But don't keep pushing or pursuing a plan that shows little hope of getting financed or being viable. There are too many good opportunities out there for you to pursue. Don't get stuck with just one.