For me...If I can find the root and some notes in the chorus or certain changes in the song, I can usually figure it out. But, I try to play it two, three or more ways. Use chord inversions, partial chords, etc. When I see a band in concert unless they are stuck to a click track, they usually play the song a little different anyway. One time they will play a progression in the 1st position and the next time play much of it in the second and third or use inversions where ever they can stick it in. Since they wrote the song or re-did someone else's who's to say they didn't play it right? Work out a song, arrange it, stick in an odd chord here and there and you've got your version of that song.
G1619T