I'm going to agree with everyone who says total immersion is the way to go. In order to do that, you need to choose a less popular place to study. I have run into people studying in 'attractive' locations. The tendency is to spend much of your time with the other students speaking in English. If you go somewhere with few English speaking students, and force yourself to speak Spanish, your language skills will increase much more quickly than if you don't do that. You should also choose your location wisely so that you aren't stuck trying to understand a difficult dialect. If not, you might take longer.
I just came across an interview that was conducted in 1992 in Buenos Aires with Sergio Renán, director of the Teatro Colón. Listening to it should give you some idea of what immersion might feel like if you were to choose Argentina.
If you can bring yourself to do so, close your eyes just as you click on the link. It may sound as if the two men are speaking Italian, but it's Argentine Spanish with all its Italian-influenced rhythms. In the 20th century, Italians made up the largest percentage of immigrants to Argentina'
Je gavacho,
no le avises al OP que vaya a Argentina aprenderlo. Tarderá mucho en aprenderlo. Yo lo sé porque lo entiendo, pero aprendí 'argentino' muchos años después de aprender el castellano.
I posted the interview at #11 not to recommend that the OP go to Argentina for immersion in the language, but as an excellent example of what Spanish sounds like there. It might be helpful to the OP if other posters could find similar clips that are good examples of how Spanish is spoken elsewhere.

It has been a while since this thread started, but I found this to give an example of Spanish diversity. I think it has been on here before.
Following NA's suggestion:
Below is an example of standard, relaxed and conversational Mexico City Spanish. (All participants are from Mexico City and they are discussing Obama's visit to Mexico):
[https://www.youtube.com/watch?v=H-Nv21bYrIk]
On the other hand, the song linked below is written in very heavy Mexico City slang (people from other parts of Mexico might have trouble understanding) and with a thick working class accent. Certainly not practical for anyone trying to learn Spanish but it's a funny song nevertheless:
During my second semester of taking Spanish in evening classes, our teacher played a tape on which the same text was read by native speakers of Spanish from various countries. I suppose the tape was some kind of teaching aid.
In any event, when one of the speakers began to read the text, I burst out laughing. If you pronounce the following as if the "words" were spelled in American English, here's more or less what he said:
FREN-tay-ah-yoo-MOO-ro, ee-ah-LOW-tro-LA-doe-oom-BO-kay.
I had just returned from a trip to Argentina at the time, so I recognized the accent. Written out, the text would be "Frente hay un muro, y al otro lado un bosque." There was only one S in that bit of text, but Argentines tend to swallow them wherever they pop up.