Watch the Harmonizing online guitar lesson by Joe Dalton from Acoustic Blues Handbook
To perform these harmonized patterns, I think of each of these harmonized notes as chord forms. So each beat is a chord change. The first chord is an E7 chord. The second chord may be a new form, but there are only two fingers for the double passing tone A chord. Remember to practice slowly. If you work on it slowly, you will save practice time. Practicing it the wrong way, whether it be a wrong fingering or a hitch in the rhythm (not playing smoothly), will result in getting better at doing it the wrong way. In other words, repetition at something done the wrong way, no matter how you may be thinking of doing it the right way, means you are rehearsing the wrong thing. Be meticulous in your practice and it will pay off sooner than you think.