There are three parts to a successful pitch:
You: what do you have to say about yourself to make people take you seriously. THEY DON’T WANT YOUR LIFE STORY.
Your audience: what do they need, how can your idea help them. DO YOUR HOMEWORK!
Your message: use stories, use metaphors, use evidence. DON’T USE JARGON OR BULLSH*T
There are plenty more techniques to help you sell your best ideas here.
And an interesting development from Nat West – an iPhone app that helps you structure a video pitch.