You got some good answers, that's great. I'll add a few tips myself. Given that you are in NYC, there's couple of websites that organise Francophile meetings every now and then in NY. One of them is called Voila New York. They meet somewhere in Manhattan every couple of weeks. Great fun, you'll meet French people, you'll be able to practise and you'll meet other Americans learning like yourself.
The Alliance Francaise in New York is a bit expensive but they do have great teachers. You should check it out..
Another association is called Acceuil New York. I believe there is an American girl there who organizes Franco-American discussion classes. It's cheap from what I remember
There are many many ways to learn it, but like the others said, conversation is going to be the key. If you want you can email me I'll give you some more details and more tips
I'm French living currently in the US