If you are pitching your idea or services to multiple parties, the one thing you do not want to do is send out a general form letter along with a standard brochure or stack of resumes. That sort of 'one size fits all' approach cannot substitute for a real proposal. The goal of a proposal is to persuade the client or boss to endorse your idea and let you do the job. To succeed at convincing them, you need to focus your message to a specific situation, gain their trust and show them that you know what you're talking about and can deliver what they need.
When new freelancers are creating a business proposal template that they are going to use often, they usually miss the most important pieces that make the difference between a good proposal and a proposal that sells. By emulating the sales process, you can create a proposal that solidifies the relationship that you've built with a prospect, and reinforces the close of your sale.