Watch the The Train online guitar lesson by Robbie Calvo from The Rhythm Architect
We have two really solid guitar parts now playing with the rhythm section and it's already sounding pretty full and groovy. How about adding a single note line riff that repeats over the groove? The riff I played is basically the lick from 'Crossroads'. The notes are derived squarely from the open position E minor pentatonic scale. It's a pretty simple idea that I think really drives the groove along and gives the listener something interesting to listen to in the way of a musical 'hook'.
The riff is rounded off nicely with some minor 3rd double-stops that slide from the C#/E into the B/D that give us chord tones of an E7 chord.