I've found that the most useful way to learn languages is to talk to people who speak that language, and try to pick up some of the things they say.

I've taken three semesters of Spanish, and what I retained from that was barely the basics, yet, I've learned many skills, and greatly expanded my vocabulary from listening to my friend speak in spanish, and trying to converse in spanish with them, wihle asking questions, about meanings.


Hope this helps, though most stuff has already been said.