If you find a bug, write out how to make the bug happen repeatably, and then post it on the Bugtracker!
Our bugtracker, the the Shoebot Trac, requires you to create an account in order to create new “tickets” for each bug you find. (Be sure to set a priority level!)
Missing features are a kind of bug, too. You can imagine new features and post a request for them on the bug tracker in the same way.