I've been to india quite a few times. Don't use your left hand for anything, especially handing someone something. Be very careful and pay attention crossing the street, a bus or auto rickshaw will hit you and keep going. Don't get upset if you get charged more as a foreigner or get presented a camera fee, its standard practice. Don't eat anything that isn't cooked and that includes yoghurt since its sometimes cut with water. If the temple door is closed- do not do not go inside. If they come past you carrying an idol, don't sit, stand up. Don't worry about camera laws, police don't really care and a handful of rupees goes very far, except in temples, try to be as respectful as possible. People are awesome, they will keep feeding you until you explode. You are suppose to protest more food and they keep feeding you. Be prepared to be barefoot at lots of places. Its very disrespectful to walk near any place holy or inside a home wearing shoes, to step on books, or point your feet at people. And above anything- avoid the monkeys like the plague. They will run up and rip things away from you. God help you if you feed them.