Watch the Lullaby of the Leaves online guitar lesson by Mimi Fox from Jazz Performance
A solo guitarist is going to be using pedal point in myriad ways because it creates a sense of fullness in the harmony and it's relatively easy to master. Most of the time the pedal point is an open string and you play it at the same time as the other figure. Think about the key you are in and the chords being played. In this case I am in Cminor so the open "G" string is an obvious pedal point choice because it is the 5th of Cminor and the root of the G7 chord. The "D" string works well too because it is the 5th of G7 and is colorful, being the 2nd of Cminor. I even use the "E" bass string over the G7 which is the 6th degree and very tense in this case because it "violates" Cminor here's where you have to be daring and take chances! Trust your ears more than music "theory"!!