Watch the Shake A Little online guitar lesson by Jeff McErlain from Essentials: Advanced Blues Rhythm
We have three variations on this one, so three times through the form. For me, on any blues you want at least three variations you can mess with, which can really give you a lot to work with. Not all tunes call for it, but on something like this, we absolutely need at least three variations.
As you move through this course, you'll see a number of repeated chord voicings: Remember, you're not trying to reinvent the wheel. That does not mean things need to be boring or repetitive, but when playing in a classic blues style there are certain voicings that define the genre. Keep your tone fairly clean or completely clean when playing this one, that way we can hear all the chord voicings clearly.