Watch the Worry Wart online guitar lesson by Chris Buono from Guitar Lab: Blues Progressions
Driving the 8-bar blues progression home here's another example within yet another standard set of changes. The progression at hand is from a tune called "Worried Life Blues", but the arrangement was influenced by modern blues great Robben Ford's version heard on his Mystic Mile CD.
Some things to watch for is the recurring tritone sub anticipation in bar 4 where the G7 is played off the 2nd 16th of beat 4 setting up the C#7 in bar 5. There's also an interesting chromatic turnaround in bars 5 and 6 that starts off on the I7 but then jumps up the VI7 (A#7) and descends from there to the V7 (G#7). Just like Jonesing for Trouble the third run through throws some tasty altered chords at you so stay alert and be sure to examine the voice leading to uncover the inner workings so you can start dropping harmonic movements like that on your own.