Song and Performance Breakdowns
Ain't No Sunshine (John Mayer)
The main technique Mayer uses for the rhythm is his classic fingerstyle technique whereby he uses his thumb to play the root of the chord and keep rhythm, and his fingers to flesh out the chord and play phrases. For the most part he is playing in G Minor using the first pentatonic position mixed with the 4th position in D Minor to create the riff. The turnaround then goes to D Minor and C Minor 1st shapes. Try putting on a drum machine and riffing with these shapes like he does.
Extra: Mayer is really leaning on the b7 in all his phrases, and adds the 5b (blues note) and major 6 to really give it a smooth bluesy feel.
Into the solo, and most of these phrases aren't complex in terms of technique, but the real quality of them is in the feel. Really digging into the bends and doing little throwaway notes give these phrases a vocal quality and build tension which is then capped off with a 5's run down the pentatonic. Generally to build great solos, you need to move yourself to higher and higher positions as you play your phrases, and this is a great example of doing that. We initially start in the 1st and 2nd Minor Pentatonic shapes, before moving up to the 3rd and 4th, and then finally the 1st shape again an octave higher. Notice also how over the change to Dm and Cm Mayer outlines that with his phrases (highlighting D F and A over Dm and C Eb and G over Cm). Here are some of the specific more interesting phrases.
Hey Hey (Eric Clapton)
This performance is one of the standout examples of great blues fingerpicking. No matter how tricky the lead parts, the key to nailing the riff is to focus on making sure your thumb is nice and steady; everything else revolves around that. Outside of technique, the song follows a very simple 12 Bar Blues format, and is a great gateway to jamming out your own bluesy riffs over this progression.
Nobody Knows You (Eric Clapton)