The guitar scales fret-board diagrams shown below display the D Dorian Scale Mode. The Dorian Scale Mode is the 2nd degree of the Major Scale (Ionian Mode). In playing scales on guitar the big confusion of understanding major scale modes is that people think your playing in another scale. It is the same scale of the major scale but your start note is the second note of the major scale and ends in the second note of the next octave. The D Dorian for example is still the C Major Scale. The root note is outlined by the note in the square of the guitar scales fretboard diagrams.
The scale formula of the Dorian Scale is (1, 2, b3, 4, 5, 6, b7). The minor 3rd (b3) of the scale makes it a minor sounding scale. The only difference between Dorian Scale and The Natural Minor Scale (Aeolian Mode) is the raised Major 6 (6th) from a Minor 6 (b6).
The Dorian Scale has unique tonal personality which reminds me of the background music in a western movie like a cowboy riding off in the sunset. The guitar fret-board fingering diagrams below show the intervals, notes, and finger placement for 2 octave fingerings. Practice these fingering and carefully listen to the sound while you play the notes and really hear what the Dorian Scale sounds like. Related Post > Understand Major Scale Modes