Watch the Shades Of The Duke: Solo 1 online guitar lesson by David Blacker from Swing Blues Survival Guide: Lead
We open this piece with a great melodic arpeggio based riff. The first 3 notes outline the I chord, and then second 3 notes outline the IV chord. This type of passage works really well on a blues with a quick change to the IV chord. But even without a quick change, it's very melodic, it implies the IV chord change, and all the notes fall within the Bb major scale so it works either way. We also have the resolution to the dominant 7th (6th fret D string) that sets up our change to the IV chord.
Over the IV, we bring in the 7b9 sound over the 2nd measure of the IV to create tension and set up our transition riff into the turnaround. The 7th & 8th measure transition riff is mostly based off of a Bb blues idea, but it incorporates a pedal off of the root on the 6th fret of the high E, which creates nice motion, and implies chord movement into the turnaround. The II-V-I turnaround is navigated using 1 note - the G on the 5th fret of the D string. Sometimes leaving space is the best idea, and Duke does a lot of that very effectively. The solo ends with a nice uptown bluesy riff off the 9th degree of the I chord.