I discovered a great blog just a few hours ago. Although it's been inactive for a few years, but the Hamsterprophecy blog has some interesting tidbits of information in its archives. As a game designer, I was immediately drawn to the RPG Design Handbook pages.
Check out the The Power 19, which bills itself as a 19-question framework for game design. I've been spending the past hour or so going through my works-in-progress and doing my best to answer every question. It has been helping me clarify the focus and priorities of the games, which is what I expected it to do.
What I wasn't expecting is that the questions have been helping me to come up with new ideas and mechanics that hep to reinforce the themes of the games. I'm not trying to weigh in on the whole "the system must match the setting" argument; all I am saying is that if you do want to design with that paradigm in mind, The Power of 19 is a great way to get your thoughts in order and come up with a solid design strategy.