Writing a RPG follows the same principles for me as writing a story. You still need to have a clear idea of what you want to accomplish. You still need to make sure all of the pieces fit together. You still need to make it entertaining for the reader. If anything, being a gamer makes me a better writer because it forces me to think things through. Pen and paper games force you to be creativeto be a problem-solverto think on your feet. Those are useful skills for a writer as well.