Watch the A minor Blues: 3rd Chorus online guitar lesson by Robben Ford from Riff Revolution
For our second four bars, I'll show you a very classic bebop and jazz move that you can use in these kinds of chord progressions. Here I'm adding the altered V chord at the end of the D minor chord. You can make these kind of movements even though they aren't written down, as generally people are turned on to them. You "wake" the whole thing up a little bit by throwing in a surprise. Most good jazz musicians' ears are wide open and they hear it very quickly and respond.