Enjoy it; you'll feel like you're getting thrown in at the deep end but its a great experience and Indians are extremely friendly in the work place, if a little shy at first. Eat with them at lunch and don't get sucked into an expat bubble. If they invite you out to places join them just to see what its like.
Despite what people say about call centres, education etc you will find that (nearly) all Indians in the workplace work very very hard. If you go there thinking you're better than them and act condescending towards them you will find yourself alienated pretty quickly and it would make your experience much less enjoyable.
You will get sick no matter how careful you are with your food and drink; that said, don't let your standards slip. Buy proper sealed water from a trustworthy seller.
Get all your vaccinations done too beforehand.
Get used to them staring too, it is pretty rude but they will stare at the foreigner.
Street food can be ok providing its deep fried and not meat based as long as you watch the vendor fry the food you're about to eat and serve it to you straight after.
If theres a Culture Shock book I'd recommend you buy it.
My family are from India (I'm Anglo-Indian) and I have travelled and worked there extensively.It will be what you make of it, but hopefully you will enjoy your experience of India.