My best advice is to get the right people on the team. At DevOpsDays Chicago we have a great team, and I know from working on some other community projects that this is hard to find. Having a "core" team of 2-3 people who have the time and energy to contribute, and get along well is crucial. Then, you can add more folks who may have less time, but will help you move the project forward.
The biggest challenge I had with other community projects is that people sign up for more than they have time to deliver, and then go dark.
This one is not easy to solve. Communicate your contribution expectations clearly from the beginning, and hone and reiterate them as you go. And expect that 30-40% of folks that seemed enthusiastic in the beginning will drop off the project.