I love game design. Creating a game is really a Generalist art. Not only do you have to be good at math and writing, but you also have to know a little bit about history, geography, politics, sociology, biology, cartography, physical science, and a wide range of other topics. Plus, you have to be familiar with the library of games and game ideas that exists in the world. It is an exacting discipline, one that takes years to truly master. I won't claim to be a Master Game Designer - I'm still learning.
I've been involved with a few game developments over the course of my designing career, and they all follow virtually the same steps:
In Conception, several random ideas come together and try to form a game. You can get quite a fair piece down the road designing the game before you get to the next phase. Essentially, in this phase you are throwing things together and seeing if they stick. Part of this phase is doing a lot of absorption of research materials - but you have to be careful what you absorb. You don't want to unconsciously plaigerize a modern piece, especially a copyrighted one.
For example, during Wraith: the Oblivion, I never once saw "The Crow" until the very end of the production process. This was because I didn't want Wraith to look like "The Crow" on purpose. Of course, in the end it turned out very much like "The Crow" because it picked up on certain key elements that are just part of the culture. But, it was important to me that the vision of Wraith: the Oblivion go untainted by "The Crow." On the other hand, there was another game out around that time called Lost Souls, which was a horror game about ghosts. I did read that, because I knew it was nothing at all like what I wanted Wraith to be. I also watched some horror movies and read books about ghosts and ghost behavior.
This next phase involves throwing everything out that you got in the first phase and starting over from scratch. You must be merciless in getting rid of everything - you start over, as if you had completed a game and then destroyed it. This is a vital step, because if done right it can imbue the game with a certain mythological depth.
Reconceiving an entire project is difficult, but important to do. The shattered remnants of the old game are laying on the floor. The game that is to be is still in your noodle. It's time to take stock of the old game - figure out what went right, what went wrong. What is appropriate and what is not appropriate. Remember your marketing - what demographic is this focused on? Are there enough people to play this game in the whole world? (To this day, I have yet to hear of someone having an ongoing Wraith campaign - we should've listened to our core audience on that one)