Some of the coolest guitar sounds are basically laziness with a music degree: you let two or three open strings ring like a stuck doorbell, move a chord shape around on top, and then pretend you planned the whole thing. That is the entire trick behind an open-string riff, and yes, it sounds far fancier than it has any right to.
This is a 19-second clip where I do exactly that — sliding little triads (or just a bare interval) up and down while the open strings drone underneath like a very patient bagpipe. It is a drone-guitar idea you can steal today, and there is a PDF and Guitar Pro file if you want actual notes instead of my vibes.
How the open-string drone trick works
The open strings act as a pedal tone — a fixed anchor that refuses to move no matter what you do above it. When you glide a triad or a two-note interval up the neck over that drone, every position bumps into the open strings at a different distance, so one shape magically becomes a whole parade of chords: some lush, some spiky, some gloriously "wrong" in the best possible way. If you want to know what those shapes actually spell, that is just triads and inversions meeting a stubborn open string.
Concrete takeaway: pick two open strings (say the top two), grab any small shape on the strings below, and move it one fret at a time. Let your ear flag the combinations that give you goosebumps and write those down — congratulations, you just did songwriting without noticing.
Fair warning: once you discover open-string drones you will put them on everything, including songs that absolutely did not ask for a medieval bagpipe. Worth it. If you want the PDF, the Guitar Pro file, and my original videos, they live over on Patreon.