For the main D minor section in 6ths, keep the tone and volume of the treble notes nicely balanced. These 6ths almost always occur two strings apart so use the first and third fingers of your picking hand (i and a) for the most ergonomic hand position. At bar 3 you will need to switch to a half barre at the 3rd fret half-way through the bar. On the fourth quaver beat of bar 21
Bb we are required to play the with the second finger in order to keep the bass note F sounding (also bar 23). This is awkward, so relax the hand in order to ‘squash’ the second finger in behind the fourth on the upper D note.