India, my beautiful country is HUGE in size and VAST in the things it has to offer. With every kilometer you move away, you will witness change in not just its landscape but its culture, language, cuisine, costume, spirituality, religion, wildlife, art, architecture, people & their physiology, politics, and just everything that you can imagine.
If you wish to visit and explore India and do not know where to begin with, I say there is no one definite answer. You can refer my compilation of state wise travel itineraries, experiences, must-dos and must-sees from every place that I have visited.
Where are you planning to visit? Let me know if you need any help!