Cant say I have travelled everywhere. But I have been around a bit in India and have read enough travel mags and books to be called something of an authority. Here is some advice:
Never, ever believe travel guide books or be fascinated with brochures from the information office. Never plan a trip based on the photos you see, they are never so good in real life. I had a hands-on experience last year. I had planned this whole trip around South India. We did cover a lot of places and had a marvelous time. But the places were of major disappointment. None of the temples and the paintings were as good as they had looked on the advertisements.
Also, talk to the local people. The purpose of travel is to meet people and interact. Talking to locals gets you the best deals as to food, shelter. They will also let you in on the places that are no where mentioned in guide books. I found out about Dhanushkodi when talking to this policeman in Rameshwaram. I am not fluent in Tamil but some sign language got us to one of the most amazing places I have ever been to.
Thirdly, don't travel with a fixed plan. Have a general idea where you want to go but keep some time apart to discover. That is where you will find all the adventures. The path along the road less travelled is where the mystery of discovery lies.