When you are trying to get people behind your idea they are probably (internally) asking themselves two questions:
1. Is this idea worth pursuing?
2. Can this person or team deliver the idea?
You've probably heard a lot about the first question. Let's consider the second. Things like credibility, your track record of success and your understanding of the field all factor into the second question.
The sort of smart people you want on your side (fellow artists, volunteers, etc.) have probably heard all of the good ideas. They understand that the difference between an idea failing and working is all about execution. Execution is all about people.
That's why one of the most useful things you can have on your "resume" is a history of starting and finishing projects. They don't need to be big projects. A bunch of small ones is fine. You have to be able to show your ability to get things done.
Sometimes when people say "I don't like your idea" what they are really saying is "you can't do it." A demonstrated ability to complete projects will help you jump that hurdle.