What are the different tunings for guitar and how do they affect the sound of the instrument?

The most common guitar tunings are standard tuning (EADGBE), drop D tuning (DADGBE), and open tunings like open D (DADFAD) or open G (DGDGBD). Tunings affect the sound of the guitar by changing the pitch of the strings, which can create different chord voicings, resonances, and tonal qualities.