Hello, Dan here!
This video is part of a series I'm doing on some basic guitar theory and practice that will help you become a more rounded and creative guitarist. This one introduces the concept of intervals.
A solid grasp of intervals – that's to say the harmonic 'distance' between notes and the names we give to those relationships – and the ability to recall them can really propel your understanding of music forwards. There's a way to do it that is so simple it's almost cheating. The fact is, you already know all the intervals in an octave: all 12 of them.