If you want to make new friends, there is no use in just saying hi to people, something of value should be exchanged or there should be a common activity. That's when they become friends. Real friends.
I've added a page on my wiki to list the type of common activities possible in India right from cycling to movie appreciation. Let me know if I can add more variety to the given mix of activities. I'm interested in figuring out what activities do people take up.