Having a great idea and getting someone else to buy it are two completely different things. In this older essay that he identified as one of his favorites, Scott Berkun offers some useful advice on pitches.
He notes that buried in any pitch is the notion that something has to change. Berkun:
Ideas demand change. By definition, the application of an idea means that something different will take place in the universe. Even if your idea is undeniably and wonderfully brilliant, it will force someone, somewhere to change how they do something. And since many people do not like change, and fear change, the qualities of your idea that you find so appealing may be precisely what make your idea so difficult for people to accept.... So when your great idea comes into contact with a person who does not want change, you and your idea are at a disadvantage. Before you can begin the pitch, you have to make sure you’re talking to someone that’s interested in change, or has a clear need that your idea can satisfy.
Pitching is one of those skills useful to anybody, whether that person is summarizing the conceptual strength of a grant proposal, thinking anew about an art project or seeking funding from a roomful of venture capitalists. Berkun's post walks any would-be pitcher through the questions she might want to answer before trying to make the sale.
Have a great weekend!