learning language

Hi, I'm a linguistics major and am embarresed to say that I don't fluently speak another language besides English. My goal in life is to speak at least 5 fluently, but I have to start with one first. (preferably Polish, French, and a Celtic dialect along wit other languages) I love language so much but just haven't gotten the change to learn what I would like to. So my question is, what do you think the best and most effective way to learn a language is (besides going to the said country)? Any suggestions would be greatly appreciated. Thanks.