Go live in a Spanish-speaking country, or if you can't do that, get a significant other who speaks Spanish as a first language.
You will not learn a language until you are forced to use it every day, in a variety of situations.
Yeah, reading, listening to the radio, etc... those are all good things, but there's nothing like total immersion. It scares the shit out of me but I can't say there's any better teacher... it's the only way I've learned Icelandic and Thai somewhat decently, and I have a long way to go.