[dholowiski]

Not for an unfamiliar project. But I have written a bit, for projects i Use. In the past I contributed to the WordPress documentation because I was using it crazy. Recently I contributed to the Chef documentation because I was using & learning it, and found a mistake in the documentation.

I would say if you want to contribute to the documentation, actually use the software (even just in a test environment) and look for holes in the documentation... little pain points like that really important thing they forgot to tell you about installing it, or additional things like how to back up the data.

Just like contributing code, don't try to write big parts on your own at first. Look for little things to fix; missing words, incorrect logic etc.