Watch the A Dorian Mode online guitar lesson by Brad Carlton from Guitar Lab: Dorian Dominance
This lesson involves a four note per string layout of the A Dorian mode without any duplication. What this means is you are going to be covering a lot of fingerboard. Your diagonal line of information will be from left to right and will require you to clearly see the notes. Each scale form is labeled according to the lowest note on the sixth string.
As you study the A Dorian mode, you will notice patterns emerging with regard to adjacent notes in the scale. Be sure to memorize the intervallic pattern of this scale. All you need to remember is that the half steps occur between the 2 and b3 and also between the 6 and b7. All the other scale degrees are a whole step apart. This means that if you're viewing groups of four adjacent scale tones, they will fall into the following patterns: whole step half step whole step (1 2 b3 4 and 5 6 b7 1), half step whole step whole step (2 b3 4 5 and 6 b7 1 2), whole step whole step half step (4 5 6 b7, b7 1 2 b3), and whole step whole step whole step (b3 4 5 6).