You may not have thought much about your competition or outsourcing some of your work, but things like that will impact your ability to make a profit. And you will find this especially so in the beginning phases of your business. Even you are just opening a lemonade stand in the front yard, you will still need to know what Susie is selling her lemonade for on the next street over!
Contextualise Your Budget _ Of course your budget will be extremely important. But sometimes people sort of pluck figures out of thin air, not giving it the context it needs in the business plan to make real concrete sense of how that budget is going to work. So it is crucial that every time you mention financials in your business plan, to really give them the correct context. When I have worked with clients in developing business plans, there has been a budget or amount set aside for example to be spent on marketing, which has been decided a bit arbitrarily. I mean with no real research, no understanding of what that amount needs to be spent on, and what that budget will truly achieve. It seems to have been put there to fill the need to attribute a certain sum to marketing. Make sure you are researching each point of your budget, make sure that you are giving it context and it makes proper sense within your overall plan.