The first part is a repeated idea over the E7 chord. Instead of just sitting on the E7 chord for 4 bars like in many traditional blues songs, this example moves between E7 and B7 (I7 / V7). Moving to the dominant help add interest and create movement which is especially important in cases like this where the tempo is slow. The second half of the fourth bar descends chromatically from B (V) down to the A (IV) in the first measure of part two. This is a common substitution over a blues progression and can most commonly be heard as a ii-V to the IV chord (which in this case would be Bm7-E7 -> A7).
For the majority of this lesson, you will be using your thumb to play the notes on the E/A/D strings while the index, middle, and ring fingers play the G, B, and e strings respectively. It is also very common in this style to give the low strings a bit of palm muting. This can also prevent the bass notes from overpowering the melodic and chordal segments of your playing.
The second part deals with the A7 chord. This example uses the same dominant change as the first part (A7-E7 // IV7 – V/IV7). Part two ends with a A#dim chord that is used as a passing chord toward the second inversion E7 chord that begins part three. This creates an ascending chromatic lines in that bass from A-A#-B that helps tie the chord changes together smoothly.
Part three begins with a E7/B voicing before again using another diminished passing chord before landing on C#m7 (vi7). This continues the ascending chromatic line that was started in the previous part. At the end there is a ii7-V7 leading to an F#m chord. This uses something called a tritone substitution which switches the V7 to another dominant chord a tritone away. What would normally be G#m7-C#7 becomes G#m7-G7
The fourth part is a normal ii-V leading back to E7. The first bar ascends using voicings from the chord scale and inversions of F#m7. The second bar links two B7 voicings with a short scale melody. Do your best to keep the first chord ringing while playing the scale line.
The final part is a traditional blues turn around using eighth note triplets. There are a number of different ways that this kind of turnaround can be played, but the use of wide intervals in this one keep it sounding more current than others.