How can I remove or lessen my American accent in my Spanish?

Hi all, I live in New York City but all of my extended family lives in Medellin, Colombia. I'm looking for help (or at least a tip or two) in sounding less American in my speech. I understand, read, and write the language perfectly but anyone that hears me talk can tell rapidly I'm American. Can anyone give me a tip or two on how to sound more native in my speech? I'm open to any idea whatsoever

Uhm... That's pretty broad... Do you have any specific issues with Spanish pronunciation? As long as you roll and trill your r's, stress the proper syllables, and avoid diphthongization, you'll be fine.

Watch alot of Spanish TV, and try to reproduce the exact same sounds, it'd easy because you already know the language.

Daniel, you should try some modelling work. It's very effective.

You'll be shocked to hear how bad your accent really is, though.

Why don't you upload a recording of yourself speaking Spanish?
Then I could give you advice in detail:)

Yeah, the first time I heard myself on tape recorder I was shocked how bad my accent was, but now I'm commited to fixing/lessening in.

Specific problems with my Spanish would be "rolling" my R's, I can do it some words like "gracias," but when it comes to words like "declarar" I can't roll the R

My advice is that you learn the lyric(that are on the video) of the songs below, for instance, a try to repeat several times and you'll see every time you do it your pronunciation will be better. Try it out and tell me if it works. In spanish we say : El que la sigue la consigue.
http://www.youtube.com/watch?v=5_Iel-u709A&mode=related&search=
http://www.youtube.com/watch?v=vrOPE6iFu-E&mode=related&search=
http://www.youtube.com/watch?v=Lvu2K08PBis&mode=related&search=

<<Specific problems with my Spanish would be "rolling" my R's, I can do it some words like "gracias," but when it comes to words like "declarar" I can't roll the R>>

You should not actually be rolling your r's in those words. Rather, you should be tapping them, in a manner similar to the T sound in English "city".

exactly, the Spanish 'R' is like the English 'T' in 'Water' or 'City', the Spanish 'RR' is where you have to roll it.

Try not to say the word "hamburger" in an American sounding way, and nobody will think that you are a gringo.