I just passed my Norwegian language tests for immigration - got highest levels on oral, writing, reading and listening (yay me!) I've been living in Norway for 10 years now. The first two years I tried to get into the language courses at the university where I was working, but because I was on a year-by-year contract I wasn't high priority. I was number 180 on the waiting list year one and number 75 on the waiting list year two. I just learned on my own.
Here's my tips:
Watch movies in the language, with subtitles in the SAME language. Don't put English subtitles on your Spanish movie, put Spanish subtitles on your Spanish movie. You can read along and hear and it doesn't matter if you understand only 10% of the words. You'll pick up context and common phrases and even slang expressions. You get to see how the words are being pronounced. Watch one movie per week. Go back and rewatch your favorites, you'll find over time you understand more and more. Try to speak the lines along with the actors.
Learn songs in the language. Even better if you play guitar or piano and can play and sing along. Songs are some of the best way to memorize words. Run the lyrics of the songs through google translate and compare so you get the gist of what is being said. Try to learn one song a week.
As mentioned here, read children's books. Rhyming books, Doctor Seuss translations, Richard Scarry books, anything. Work your way up grade levels. If you can get ahold of 1st-2nd grade school books even better. Memorize children's rhymes.
Norway has a service called Klartale (clear speech), it's a simplified news service with easy words and very well pronounced Norwegian. You can read or listen or download podcasts. Maybe there is something similar in Spanish? Download podcasts or children's stories and play them in the car. Don't understand? Doesn't matter, try to repeat the sentences and phrases you hear. It may help to imagine you're an actor and try to ham up the accent as you visualize yourself as a Spanish movie star. It's partly about the mindset.
I bought the Pimsleur Norwegian courses. I think for Spanish they offer 90 lessons. It's (almost) entirely listen and repeat, which means you can run the lessons in the car or while walking to work. I had a half-hour walk to work which is the length of the lesson, so I did a lesson a day, once on the way to work and then repeating it on the way home. I recommend these. (I did 10 lessons in Spanish when I was going there for a conference and learned enough that I was able to ask someone on the street for directions to a pharmacy and understand enough words he told me to be able to find it.)
Extreme case: Immerse yourself in the language by moving to the country for 10 years. Be extremely frustrated for the first 6 years that you are living in a fog and not understanding shit. Be satisfied if after 10 years you can get by and don't care anymore about liberally mixing in English whenever you don't know a phrase. Tell yourself that the natives think it's charming how you mangle their language in amusing ways.