When you have some experience with haXe, you will certainly feel the need to participate in the community and help, as you have been helped. There are several ways to do this.
At first, and that is certainly the most obvious part, you can answer people's questions on the mailing list and on the forum.
If you do so, do not hesitate to give some advice. Share you experience—people who are migrating from the same language as you (if you are migrating) may want to hear about your experience.
Another way of participating on the mailing list is by making some proposals. If you think that you have a great idea that can make haXe even better, or can help newcomers, or everyday development with haXe, then ...