How can I properly tune and adjust my guitar to Drop D tuning while also ensuring the fretboard is correctly set up for optimal playability?

To tune your guitar to Drop D tuning, first tune the low E string down to a D note. Then, adjust the tension of the other strings accordingly. To ensure optimal playability, make sure the fretboard is set up correctly by adjusting the action (string height) and intonation (accuracy of pitch across the fretboard). You may need to make adjustments to the truss rod, bridge, and nut to achieve the desired playability.