Don't get irritated if people at trains or public gatherings ask you many questions. Questions that would sound rather personal from western perspective are so common from Indian point of view. These may include enquiries like How much you earn? How old are you? How much this cost? Are you married? etc., This is the way a common Indian tries to get interaction with a stranger. There will be nothing except curiosity behind these questions. Answering these questions with a smile would make you appear friendly and you surely would be going to win their hearts. An average Indian would certainly treat a foreigner as his guest and comes forward to do any help they can. A friendly gesture and a gentle smile always have a very good effect.