Documentation
Improve, Update, Translate
Mainly the documentation is inside the wiki. So if you read the articles in the wiki and feel, that something is wrong or missexplained or can be more detailed, don't hesitate to change it or make additions. And don't be afraid there is nothing, which can go wrong. The wiki has a version control, so old articles can be restored at any time.
But even if you are new to LinuxMCE and make your first installation, why not post your expierence with the hardware in the wiki. So all user after you, have a good starting point, hunting for compatible hardware.
Not much timeMaking corrections to an article you just read, doesn't take that much time, but is helpful for all other people.