I would suggest lots of listening on topics you're interested in, along with reading topics you're interested in. I'm interested in space, so I'll spend some time watching videos on JAXA's YouTube channel, which has some really interesting stuff on it, by the way. There are also news sites where they'll have the text of the story that you can read along with as you listen. In the end, though, what it's going to come down to is exposure. You just have to be exposed to the language a whole lot. This reminds me of situations when people would see me looking at a Japanese website or something and make some comment about how I'm always looking at Japanese, usually along the lines of "why do you do that?" to which I'd reply, "I'm not going to learn Japanese by not doing Japanese."