Watch the Elementary, Mr. Watson online guitar lesson by David Blacker from Swing Blues Survival Guide: Lead
There are a couple of characteristic Junior Watson-esque elements in this piece. The use of melodic call and response lines in the first few measures is a unique way to open a Texas style shuffle like this. It's not a typical sound and immediately grabs the ear. These phrases also incorporate a bend from the sharp V to the VI, which is a great west coast styling. The sharp V is an "out" sound, but when you bend it up to the V (a major chord tone) it creates a great effect. I recommend experimenting with half step bends into chord tones, as it can immediately help you spice up some of your existing lines.
The riff over the IV chord features a great trill from the 6th to the 7th, which really spells out the IV chord. The long trill occupies most of the 5th and 6th measures, which is another kind of characteristic Junior Watson styling, and a unique sound for a shuffle like this.
One main takeaway of this piece (and Junior Watson's playing in general) is to get creative and flip musical ideas on their heads. I think this creative approach to bluesy elements is what really separates Junior's playing from others, and an inspiration to break out of the old patterns and habits that many of our musical ideas tend to get stuck in.