The general fault of indie game developing is the lack of proper motivation. Most just try to grab some money without real development team, and hope to live of it. Now, that can work, but rarely. Succesful attempts at that are succesful under many conditions: being meticulous with development, aiming for lowest common denominator gameplay, not trying to innovate and preferably clone popular mechanics, and having discipline to ship it. Examples: Cyclomaniacs, Burrito Bison, Kingdom Rush.
In my book, that's not indie, it's built on monetization from starting game design. And that's precisely why it fails.
The process at most sucessful indie games was actually quite opposite. Let's create something we want to play, and meanwhile or even just at the end of it, try to monetize. Or not even bother with it. Examples: Braid, World of Goo, Meatboy.
EDIT: Added some reference game titles.