We can make the blues more bluesy if you alternate between 2 versions of the 1-chord. For example , in the key of G, we can do a G7 down the neck and alternate that with another G7 up the neck, On the guitar, this could be a G7 using the E-form using a bar at the 3rd fret, alternating with a G7 using the A-form with a bar at the 10th fret. If you emphasize the bass note when doing the 12-bar shuffle, it sounds really good. We practiced this and then had one player add riff #1 while the rest of us continued the shuffle. It's important to stay together and maintain a constant tempo.