I am trying to figure out how to play this lick (the first part and how to shift it in I IV V)in the key of c. Can anyone help me out? The song is just an example, it's used in many many blues songs.
Straightforward. Play yer blues with C chord on fret 3 on both E and a strings doing the riff on the E string 5th fret with Ring finger. Then for the lick use ring finger on 5th fret c and e strings and then both down to 3rd fret with index finger.
