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.
Do your research. In order to be able to write a strong, comprehensive business plan you need to possess a sound knowledge of the market you are involved in. You need to actively conduct market research and ensure that your plan makes reference to your findings. It should include factors such as market size, the predicted growth path of said market and how you propose to gain access to it. For example, if you are planning on opening a bar then your business plan should include figures based on the local population, cost of suppliers, predictions about whether the bar industry is likely to grow or decline in the area and a review of the competitive environment.
Traditionally business plans have been highly confidential and quite limited in audience. The business plan itself is generally regarded as secret. An open business plan is a business plan with unlimited audience. The business plan is typically web published and made available to all. In the free software and open source business model, trade secrets, copyright and patents can no longer be used as effective locking mechanisms to provide sustainable advantages to a particular business and therefore a secret business plan is less relevant in those models.
Once you have done all this you should have a complete and detailed professional business plan. The most important thing to remember when developing the plan is to see it as a living document and include specifics regarding dates and specific responsibilities. Your plan will need constant reviews and updates and things change so expect it to be a work in process for a good stretch of time. It will all be worth it in the end, a well-written plan will help ensure that the business is fully focused on what is required to achieve the company's goal.