What you should do is play along the music your ear knows although you haven't played it before. A simple piece of music with accented melody line is best suited for this, rather than shred-stuff. Play along the vocal line if it's colourfull enough. An excelent example would be Mike Oldfield's instrumentals, and i just ADORE playing along The Rubbetes' "Sugar Baby Love". Off course, you can play along radio, TV, computer games, a parrot (seriously!)... The point is to focus on the melody and try to reproduce it. If you have tabs for what you were playing, check them afterwards for what you couldn't figure.
Also, study music theory, and by that I mean study until you understand it, not learn it all by heart.
You'll notice that after a while you'll be able to tell a songs key and chords by just listening to it.
By the way, I asociate notes and chords with colours and moods(mind pictures which induce certain moods). Find out what suits you best. Good luck.