Planning to come to India in near future, may be for Common Wealth Games, well here's a ready reckoner to find your way around.
1. Try to have a mobile which has at least Google Maps with location finder feature. That might help you get an idea of where you are and where you are heading while commuting.
2. Try consuming Mineral Water to as much extent. Because unlike the developed world, in India... Tap water is not same as bottled water!!
3. Be careful about your luggage and belongings when outdoors.
4. Try wearing casual floaters or slippers as they would be the most comfortable in case it rains or even otherwise.
5. When you reach airport, rather than coming out and taking an Auto Rickshaw, for the feel of it, just book a cab from the terminal itself as the Auto Driver would surely overcharge you to the tune of a A/C taxi fare. You can find info about various radio cab services on Google for eg: Meru, easy-cabs etc.
6. Keep an Indian acquaintances number handy to help in case of an emergency or even just to ask directions. Don't hesitate to ask any passerby in English, if they know the language, they'll surely respond.
7. A lot of governments like Australia, have issued a long list of diseases prevalent in India, as if we are ogres living in swamps. Its not that bad at all. Just eat at proper places and drink clean water and you would be fine.
8. Our government suggested that you carry your own toilet paper or tissues as our public toilets are not clean enough. Well this is a problem even in western world, I rarely found a clean public toilet even in Amsterdam shopping malls during Christmas.
9. Don't worry about the health care in case its required. You would find world class health care facilities in India.
10. For any flight or Hotel bookings. try the travel sites rather than going through travel agents as they will surely try to rip you off.. There are a lot of good websites which may help.. For example: yatra.com, cleartrip.com(Train Booking Also), makemytrip.com etc. You'd find that in terms of Online services/bookings/shopping, India is far ahead then what you might think.
Let me know through comments in case you need any specific info... Enjoy your stay! :)