Watch the D Form online guitar lesson by Brad Carlton from Guitar Lab: CAGED Modes
This lesson presents the Mixolydian mode over the D form of the CAGED system. Diagram 33 shows the D form arpeggio in red. The three notes that form this major arpeggio are: 1, 3, 5. The formula for the Mixolydian mode is: 1, 2, 3, 4, 5, 6, b7. If you view the arpeggio as a skeletal framework of the mode, you can then perceive the remaining four notes as color tones or chord extensions. These are presented in black. It is very important that you memorize the scale degrees and to aid you in this process you will learn to organize the tones in each position in terms of octaves.