It should include a market research that identifies your competitors, their share of the market and the range of the products they produce. By learning how they conduct their operations, you may learn tricks of the trade in the business you want to enter and you also get to have a basis on what you can do to excel.
It also needs to be written in formal format and style. You have to remember that a business plan is something that you may have to present to your business partners, financial firms and banks. So if you can, refrain from using slang in any part of your plan.
A business plan should be detailed. In listing your products and services for example, you should not really stop by just enumerating them. You also should write down the descriptions and scope of your products and services, touch base on production and identify means on how you can market your "brain - child" to your targeted niche.
It needs to have a list of everything you need. Note that the word everything here comprises of the equipment, technology, raw materials, financial and other resources that you may need when starting and running your business venture. Having all these listed will give you an idea on how much capital you need before you start and how much money should you make in a day to make your business survive.