Ten ways to get (better) support for an open source project
thechangelog.com
thechangelog.com
Related to point #5, if you do file a bug, don't just file it and walk away, even if you do provide lots of helpful information. If it's a particularly tricky bug the person working on it will probably ask you for more information, especially if it's only occasionally reproducible.
#10 is important whether you're using an open source project or not, but it's especially true if you aren't going to do #9. It might be enough to keep the author working on the project.
If you have a reputation for helping other people out where you can, others will be more likely to help you out in return. Reputation means everything in an open source community. Be good to yours and it will be good to you.