One thing mentioned is that some people make extensive use of private modes of communication with project leaders. I've fallen prey to this as a contributor myself, so much that I've now made it my policy to never converse privately unless it's related to a security issue.
I think another important point is multiple channels of discussion. The project I work on has a forum where people can ask for help installing or with other issues they have. If they find a bug or have a feature request, it goes on our issue tracker on GitHub.
That's great to hear that you're forcing yourself to keep communication in the open, when at all possible. That's one of the best ways to keep a community healthy.
In my experience with a particular open source project, more than half of new contributors started by communicating privately with myself or some other leader in the project. This is only bad if the communication never moves out of private conversation. I've found it normally takes a few nudges to get people to build their confidence and participate publicly.
Interestingly, it's not only new contributors who suffer from this. I've been told by some of the most prolific contributors to our project that they are still intimidated to speak out publicly. Many times these feelings come from deep-seated cultural norms that don't really fit with traditional Western/American ways of communicating. And that's ok! We all learn together how to best communicate with each other. And we get a healthier community and better code out of it.
I think another important point is multiple channels of discussion. The project I work on has a forum where people can ask for help installing or with other issues they have. If they find a bug or have a feature request, it goes on our issue tracker on GitHub.