Religion being of the utmost importance to the Indian way of life, it is fondamental to respect the codes of politeness, usage and good conduct while on a trip to India .
To greet, you have to bow slightly and press your hands together as if in prayer, you can also accompany this with a Namaste . For Indians, the joint hands signify the meeting of the divine in the person being addressed. Joining the hands in front of the chest is the standard greeting; in front of the face is to greet a master; above the head to greet God.
In India the dress code is very important , thus what is acceptable are baggy and long clothes be it for men or women. It is also customary to take off your shoes before entering your host's house, as well as in a place of worship or a temple.
At meal time in India , it is common and even highly regarded to burp at table. Moreover, it is important to to taste each dish , even if only a little, as refusing a dish can be regarded as quite offensive. If you do not wish for a second helping, leave a little food on your plate. Also, during meals avoid serious subjects like politics or religion, prefer a family or culture centred conversation. Be careful as well of spices that can surprise your unaccustomed palate!
Touching the person you are addressing, if you hardly know them or do not know them at all can be very badly perceived. Kissing, for example, is considered a sexual act. Due to this, lovers must avoid all public display of affection. To Indians, the head is the most sacred part of the body , so never touch their head, even a child's.
However, touching the feet of an elder or master is considered a mark of respect. Indeed, feet, which are always in contact with the Earth, are considered dirty and impure. Once the feet have been touched, the person expects a blessing from the master and in particular that his head be touched. Mind, do not touch or point at someone with your feet, as they are considered impure.
Like in Turkey or again Malaysia where it is the custom to eat with the fingers, always use your right hand to eat (also to give or take an object). As for the left hand, it is reserved for performing one's ablutions and is as such considered impure.