let me try to share my experience...I receive and read dozens of Business Plan every month. They are rarely well prepared. And almost always they don't answer some key questions (e.g. as someone has already mentioned "how much money do you need?".
So, unless you are one of the rare geniuses who have set up several companies and raised millions all by themselves, you are right to look for help in order to increase the chance to be funded.
However it is also true that you should be the main player while preparing the Business Plan.
I would proceed as follows:
- choose one of the templates that other people have suggested
- prepare a first draft of your Business plan
- to finalise it, ask for help to an advisor who has experience in Fund Raising (and ideally in your industry too)
What above won't give you certainty to be funded but it will surely increase your chances.