Tips on getting your contributions accepted into an open source project

LinuxChix offers this nice little guide on the process and etiquette of contributing code to a project. It is written for programmers, as opposed to non-techy end-users. Some of the advice they give could apply to both, if you extrapolate a bit. Still, it would be great to have a similar guide specifically for non-techies wishing to contribute to OSS in ways other than writing code (writing documentation, user testing, etc).