Welcome to... "Micro-Lesson 287"
The riff begins on a "pick-up" (off of the up-beat of "2"), where these open-string pick-up notes bring in our first measure. Climbing through a popular sounding, 'open-string style' folk guitar run, we enter into the first bar of music with a, "G maj7," chord.
The, "G and F#," tones play off of each on the 2nd string, with the open, "G and D," strings performed in the background. A return to the opening, 'pick-up note,' phrase occurs next. This phrase, (acting as a theme for the riff), brings in a similar appearance of the first bar of music once again. However, there is a different turnaround segment that comes in by use of, "G Major" and "E Minor," chords.
These two chord harmonies set-up the final measures' appearance in where we find the key's V-chord of, "D Major." The "D Major," chord is inverted (in first inversion position), with it's 3rd chord tone in the bass, (F#). This allows for the riff to either be repeated, or to come to an end by landing on the tonic chord of, "G Major."
Standard, "Classical Guitar," style finger-picking is applied throughout the entire progression. The chord movements all easily support finger-picking technique. And, even though Hybrid picking could be used as an option, I would stress the use of finger-picking. For the record, I did not perform any of the takes recorded for this Micro-Lesson using Hybrid Picking. Strict finger-style (Classical method), was applied throughout. Have fun learning this riff - Enjoy!
Micro Lesson 287: "G Major" Folk-Rock Riff