Writing a film proposal requires a compelling plot, length of the work and the format, details of the intended audience and a preliminary budget. A film proposal is a comprehensive document that includes the treatment and all of the project details an investor would be interested in.
The best way to start a proposal is to write a treatment for your film. A treatment is a short story narrative written in simple language. It describes your film without any technical jargon. From there, you can start working on the other aspects that a proposal needs. In addition to the written document, a film proposal will also include a budget and a sample reel or work-in-progress edit. However, if you have been given a specific proposal format by an industry professional, then you should follow that.