Looking for the best way to learn Polish?

So I've moved into a new place and my new roommate only speaks Polish. It's very uncomfortable not being able to converse with her and it's a bit of a hindrance when we need to talk about things about the apartment. Therefore, I'm looking to learn to speak Polish. I would like to become fluent. I'm just wondering if anyone had any suggestions on the best and easiest way to do this. Thanks.