Ask HN: How do I start contributing to open source projects?

Second the suggestion of OpenHatch: http://openhatch.org/

If you are a college student, try getting into the Google Summer of Code next year: https://www.google-melange.com/gsoc/homepage/google/gsoc2014

If you are a high school student, The Google Code-In contest may be of interest (dates for 2014 haven't been announced yet): https://developers.google.com/open-source/gci/

This may be overkill, but if you want to learn a lot about the overall history/culture/etc. behind open source projects, I just wrote a blog post linking to a number of great resources. You may find some of this stuff useful, especially if you're interested in the licensing aspect.

http://fogbeam.blogspot.com/2014/08/starting-points-for-lear...

Find a github repo of an interesting project an read CONTRIB file at the root (ex. https://github.com/TryGhost/Ghost/blob/master/CONTRIBUTING.m...).

Go to github, fork something (anything you like really), add something cool to it (or fix a bug, whatever), then submit a pull request. Boom, you're a contributor!

The simple answer is: look through bug trackers, find an issue you can tackle, send a patch or pull request.

However, you might also want to check out OpenHatch.

Find an open source library you've used in a previous or current project.