Watch the The Train online guitar lesson by Robbie Calvo from The Rhythm Architect
The architecture for this 4 part blues rock groove in the key of E is built on the foundation of guitar part no.1 holding down the low end in open position. Barring the B and E notes on strings 5 and 4 with my first finger allows me to play the A/C# and D major chord move on the lower four strings. Of course I'm using the open E string as well to give me a nice low end. Playing my first guitar part in the lower register gives me some flexibility when super-imposing other guitar parts because I've left room for other tonal frequencies to be added above this guitar part.
Don't forget to try and slide into the E chord from a semitone below and also remember to push and pull the beat a little to make the part have a nice feel.