Watch the Guide Tones - Part 2 online guitar lesson by Jeff Scheetz from Blues Jam Survival Guide
The real beauty of the guide tone theory is simplicity. If you play the 3rd and the flat 7th of any chord as your 1 chord, and move it down one fret, that is your 4 chord - then move it up above the 1 chord by one fret - that is your 5 chord. So it works like that all over the neck! And can really make for a nice addition to just banging out the full barre chords all of the time.