How can I improve the sound quality and playability of my 6-string guitar through tuning adjustments?

To improve the sound quality and playability of your 6-string guitar through tuning adjustments, make sure each string is tuned accurately using an electronic tuner. Adjust the intonation by ensuring the 12th fret harmonic matches the fretted note. Check the neck relief and adjust the truss rod if needed. Finally, lower the action at the bridge to improve playability.