At my work, we recently had a workshop on how technical folks can better present ideas when trying to get funding. Here are a few of the take away points that might help you:
1) Don't focus too much on the technical details.
2) Know your competition and be able to explain why your idea will work better.
3) Practice your pitch beforehand, and solicit feedback on how to make it better.
One recommended method for getting feedback was to grab a small group and ask them to pretend to be investors. Have a few of them focus on what parts of the presentation worked well and shouldn't be changed. Have others focus on what parts of the presentation had problems. When getting the feedback, just take notes but don't try and respond immediately to the feedback. Do this a few times and your pitch will get significantly better. You may end up feeling like a used car salesman at the end of the day. But if you're going to sell your idea, you need to be able to wear that hat for a day.