There's a lot of great work can be done with improving gaming experience on KDE and making fantastic looking user interfaces. A good way for prospective KDE developers to get their feet wet is by creating their first "Plasmoid".
Follow the directions on Plasma4/GettingStarted to create your own Plasmoid. This is largely a process of copy/paste code from the guide. Though you can optionally (and should) take initiatives to make it your own, most of the work will be learning how to build and install your own Plasmoid.
While working on this task you should join and remain in #CopyleftGames on Freenode to get help, feedback, and guidance from mentors and other developers.
When finished, upload a full screen screenshot of your Plasmoid running on your desktop and a tarball of your code and build scripts to this task.