Best transport medium of India:

1.Train

2.Bus

3.Flight

Train:

Indian Railways are always best for travel a long distance across India. But when comes to reservation it's very difficult to grab your Booking. For the popular destinations, its always shows that there are no available tickets. Because most of the peoples using the train journey they tend to book before you plan.

Anyhow you can book train tickets on irctc.co.in

Bus:

Bus transport best in India I can say. Because Government running most number of buses to all popular places in India. More than there equal than more number of private bus operators in India with affordable Prices. 

For online bus ticket Booking 

Flight:

Flight travel best and quicker one but its bit expensive. If you can afford you can book.  You can book Flight tickets online in India with the following online travel Agencies

Make my trip

Goibibo

Yatra

Via

Etc etc