I've had only one experience with crowd-funding so far, and from what I have gathered from that experience, it's extremely important to build an audience way before hand.
The point of this is, you market the film, you gather interest, and you get a following going that you can somehow track, perhaps based on Youtube video hits and likes, Facebook post likes and views, Twitter notifications, blog entry views, and so on and so forth.
Then, once you have a good solid foundation in a decent sized crowd, once you launch your crowdfunding campaign and let every one of these Social Media outlets know about it, then you just might be able to get an initial flood of people excited and ready to fund your project. And then if the project gets off to a good start, and you continue to market it on your sites and in new venues as well, then the rest of the money is more likely to come.
But, if you only do minor marketing and don't try your best to build up initial momentum, then once you launch your campaign, you're likely to not get very far, and you'll only bring in the most closest and dedicated individuals: your family, your crew-members, their parents and significant others, a few interested strangers, and maybe one person who just thought it looked cool and liked one of your perks. Sometimes this can be enough, but for people like me who don't tend to be very social and do make a whole lot of friends all the time, it usually isn't.
So it was a pretty sad outcome in my case. But the film still got made, it's still being worked on as we speak, and I now have a much more realistic understanding of what might be necessary next time around to get a much better reception and response from potential donators.