Everybody is welcome to join the mailing lists and participate in discussions.
If you see possible improvements, you're welcome to contribute
patches, attached to JIRA issues.
Changes (unless they are trivial) are usually discussed on this list
to make sure we agree on them and understand them.
Once people demonstrate their skills (both code-wise and
community-wise) and show sustained interest for the project, they can
be voted in as committers by the "PMC", the project management team.
See "voting in a new committer" at
http://incubator.apache.org/guides/ppmc.html for the details.