1. Do remember that it is totally acceptable to eat with your hands, as it is a part of Indian dining etiquette. However, most people use cutlery too therefore, you can do so easily.
2. Don't offer any leftovers or something that has touched your mouth to anyone to eat, as many people find it unhygienic to eat something from which you have taken a bite.
3. Always remember that sharing food is appreciated in Indian culture. Therefore, try to do that when you're eating with someone in India.
4. Be prepared to see a lot of dishes on the table when you're invited to someone's place in India. Unlike other cultures, there isn't any system of courses and all the dishes are generally served at once.
5. Don't get surprised when your host serves you again and again. It's a way of affection, decline politely if you don't want it anymore.