We've found over the years that having one specific task for new contributors to complete makes a huge difference in attracting that next contributor. See http://mairin.wordpress.com/2010/07/23/second-fedora-design-... for a really successful effort along those lines.
If you want to join #openhatch or join http://lists.openhatch.org/mailman/listinfo/events/ and chat with us, we'd be happy to see if there are ways we can both learn from each other!