I've been using Open Source for a lot of the work I do. I've wanted to give back but with family commitments and work, it's difficult.
Given my engineering background, I thought another way to contribute was to write documentation. That is, I felt I could do some level of engineer-speak and as a user, I could merge the two. With that in mind, I wrote (and will maintain) the KDE UserBase KWin Rules document. Have a look, it's a great way to customize the windows in your KDE environment.