How much do know about Hind? Maybe you will shake your head, meaning you know even nothing about this language. But now that you need to learn this language, you need to learn something about Hindi.
In India nearly all the people can understand Hindi. It is very common if you see they communicate in Hindi. However, 70% of the Indian people cannot write this language, even the college graduates who come not from Hindi speaking communities cannot do that either. It seems that this language form is very hard to touch as an official language of India. But don't worry about it.
First, you can choose to India to learn this language. Of course this way maybe appears expensive, but probably efficient enough. When you go to India, you need to visit to the Hindi speaking communities if it is possible. Then try to learn from them. But how? You can try to get new friends from there. And when you get friends, you need to practise Hindi with them as much as you can. Yes, the first way for this kind of communication is through words and phrases. Truly you need to learn them step by step first.
Second, you must have a radio, why not use it to pick up the Indian Hindi signal to listen to. But you may say that you cannot even understand a word of it in the beginnig. It is real you cannot. You are not a Indian people after all. Then I think you need to buy a software, like Rosetta Stone Hindi, or go into some training class to learn first. It is the foundation learning. And in a training center, you have your teacher to guide you, then you can learn how to read Hindi, how to write Hindi words and so on.
Third, learning Hindi is not meaning learning its language only, but its culture as well. So many people have mentioned this aspect, but not all the people can really understand its importance and meaning. You can try to read the books about its culture. Or even sometimes you can learn its country's geography or things like that.
Certainly using a software to learn a foreign language is good. Perhaps you want to learn other languages like Polish and Spanish. Rosetta Stone Polish and Rosetta Stone German can be very useful to you.