Basically, you need to speak to people outside your class so that you don't all learn while making the same mistakes.
The first group of people to speak to are native speakers. Even if you don't have many friends from this group, there are others "on the street," the shopkeeper, the server, the cleaning lady/man. Try to speak German to "anyone" (native) even not your "friends." Also, you can learn a lot by listening to radio and TV.
The second group of people to speak to, if you have them as friends, are "non-native" speakers who come from backgrounds other than Indian. They will make mistakes, but probably not the same ones as you. You and they can then learn a lot by correcting each others' mistakes. In this regard, you are aiming for a "least common denominator" of "standard German." If you can understand people who are, in essence, speaking a different "dialekt" of German, you have "arrived."