Greetings Etiquette
In order to greet one another, Indians hold their palms together and utter "Namaste" (nuh-mus-tay). Hugging and cheek kissing, especially with the opposing sex, are inappropriate and should be avoided. Before entering a home or a place of worship (temples, mosques, gurudwaras), remove your shoes.
Do not critique the attire worn by Indians. Some folks may have a different idea of what constitutes formal attire than you do; they may choose to don a traditional kurta pyjama rather than a shirt and slacks. Do not comment on women who wear veils, whether it is the ghunghat (head wrap drawn to the chin) used by Hindu women or the burqa or hijab worn by Muslims.
The notorious head-bobbing gesture is another typical move. A nod that is vertical says "yes," while one that is horizontal means "no." Do not take offense if Indians refer to you as a "American" or "Englishman" without regard to where you are from. Many of them have a propensity to lump foreigners into one of these two groups.