Once you learn the basics of 20th century Indian history, The Great Indian Novel is an amazing book. It would be a really great guide as you go along and learn, as it recasts Indian history into a fictional story based on Hindu mythology. While that seems a bit confusing, what it did for me was make me want to know who each fictional character was supposed to represent. Once I figured that out it became a great way to guide me along in the history of India.
For instance some characters like Ganga Datta are going to be obvious--Mahatma Ghandi. But other bit players not so much. Wikipedia has a cheat sheet:
http://en.wikipedia.org/wiki/The_Great_Indian_Novel. Then you read about the bit players, and see what the conflicts described in the novel are referring to in history. Most of the time its fairly accurate.