There's lots of really good advice in this thread. It's easy to tell who knows what they're talking about and who is just a dumbass. The truth about India is a mix of what they're all saying - it's a big, complicated place.
Strangely...all of that is true to some extent. There's going to be a HELL of a lot of staring. Indians don't have any cultural taboo against staring, and as a Black man you're going to be stared at like a motherfukker.. A lot of that is just curiosity, some of it is racism. Many Indians are racist against Black men, but it's really hard to tell the difference between racism and curiosity if you don't know the language. But if you let it get to you, you'll go crazy - you have to just assume the best. If they're racist, then fukk them. 99% of the time the racist ones would never dare trying to pull shyt.
At the same time, skin color is a complex thing there, and it's not the same as racism here. As that first guy said - if they think you're a wealthy American tourist, that makes a big difference.
Nah, that's just not good advice. If they see you're a Black man, their stereotype is that you're from the West Indies (or maybe Africa if they're educated enough - it's a cricket thing), and their opinion is that you're lower than them. Being an American actually elevates you in their eyes. Obama's presence has made it easier for them to understand what a Black American is and respect it a little. I'd rather have myself known that I'm an American than have them assume African or West Indies or even British - there are still plenty of Indians that have animosity towards the Brits.
edit: Kobe is right about the "Indians hate everyone, even other Indians" thing though.
No matter where you're from, even a different region or caste or family within India, some people there will find some reason to shyt on you for something. At the same time, a lot of Indians are really fukking hospitable to guests no matter where they're from, so I just try to fukk with them and not the others.
Yeah, this is a great, balanced post. Nothing will ever prepare you for how different it is.
If you haven't traveled overseas, you really need to go with someone who is familiar or take a guided, preplanned tour. Otherwise you really, really need to stick to the easiest spots. It's too easy to get confused by the craziness or get taken advantage of by people looking for a mark.
Of course, be careful about food prep and don't eat anything that's been sitting out, don't drink anything but bottled water, expect to get sick at least once and you'll deal with it better when it eventually happens.
April-June is hot as fukk and as a first-timer I'd avoid it. July-September is rainy season, varies from miserable to pleasant depending on where you are. October-March is the most pleasant weather, though the North and the mountains can get really cold in December/January.
Some quick thoughts on a few places. I tried to loosely order them from "easiest" to "challenging".
Goa: beach resort India
Bangalore: wealthy, technological India
Kerala: educated, peaceful, jungle India
Mumbai: modern, big-city, diverse India
Darjeeling/Sikkim: mountain resort India
Rajasthan: beautiful desert/mountain India
Kashmir: beautiful Muslim India
Kolkata: crazy, vibrant India
Delhi/Uttar Pradesh/north India: the belly of the beast. Hundreds and hundreds of millions of people.
I can answer questions if you have any other specifics.
One last thing - if you go to India, you're going to see a lot of very poor people, and if you have a heart you'll feel bad for them. Giving beggars money almost never improves their situation - for the kids especially, it pretty much guarantees that they'll be forced to stay in a begging lifestyle. Most beggars really are desperately poor, and a lot of them are ran by begging gangs that take the main cut of anything they get, so the money is only funneled to someone else. They use little kids or disabled people or young women with babies to do this.
So if you're going to feel bad not giving them money, I recommend looking up an organization that does good work for the poor in India, and donating to them before you go. Then bring little candies or whatever you want to share with the kids if you want to, or buy fruit there if you like and share with them. Or every time you want to give them money, set that aside in a different pocket and later donate it to someone doing good sustainable work improving people's lives. But giving beggars money is often the worst thing you can do for them once you learn who really gets the money and how it only forces them to perpetuate the same lifestyle.
Oh, and unless you're in a really modern club for the young and wealthy, any girl who hits on you is probably going to be working. All but the most modern Indian girls are far to shy to engage in any sort of stuff with a foreign man in public, especially a black man. And getting involved with a prostitute there is a horrible, horrible idea. So better safe than sorry - like I said, unless you're in one of the really high-class clubs.
anyway except a few so yeah 
