I've added some documentation-guidelines to our wiki. We are aware how important documentation is for the success of an open-source project, and trying to continually improve here. These guidelines help deciding where to contribute, and provide a general structure for your contribution.

Have a "best practice" that came up from a forum-discussion?
Discovered a neat, but undocumented feature in one of the sapphire-classes?
Want to write a new tutorial on how to make coffee with silverstripe-functions?
Every developer who feels he can contribute knowledge is welcome to edit the wiki on doc.silverstripe.com!