What Are Guide Tones?
Guide tones are the notes in a chord which leads or gives harmonic pull toward the next chord, these are an excellent way to study and absorb the sound of any chord progression.
Guide tones are used to outline chord progressions in an improvisation. They are most of the time the 3rd and the 7th because this is what determines whether a chord is major, minor, or dominant.
This jazz guitar lesson explains how to solo over common jazz progressions by using guide tones.