The Game Begins with an Idea
The basic steps in invention are to begin with an idea, try it out, and keep tweaking and testing until it seems "good enough." It seems amateurish, but it's the same process, even in most game studios.
Many games begin with the "idea" of copying another game - but success in that arena is limited. The author suggests that the truly compelling games are innovative, and they start with a fresh idea from somewhere outside the world of video games. He suggests looking anywhere other than the gaming industry for ideas.
Some of his suggestions are trying to make a game that mimics the properties of magnets, or is based on a children's story, or that feels like a painting, or that is modeled on a real-world problem. Such an approach will result in a more original and compelling idea rather than just trying to make another first-person shooter or a slight twist on Tetris.
He then goes a bit kooky, talking about using the subconscious mind and the power of dreams to inspire creative thought, as well as some of the common tricks for brainstorming and unconventional thinking. There are much better and less zany sources for this kind of thing.