Here are a few things to know before you travel to India
There are lot of local languages
Inspite of cards, carry cash in hand
Carry light warm, less heavy winter wears
When you are travelling it is festive time, buy traditional clothes in festive sales value
Bargain as much as you can in India when you are buying
Every place has best yummy local cuisine try them for sure. Summers are from April to July, winters are from November to March inbetween months are monsoon seasons. You could decide your travel accordingly.