Start with the default setting
Check that your guitar is set to the correct setting: EADGBE. Hold the low E-string down one full step to D. Check the pitch against the fourth string.
Hold the sixth string by the fifth thread, note it and adjust the open fifth string until both strings leave the same note (G).
Hold the fifth string by the fifth thread, note it, and adjust the open fourth string until both strings leave the same note (C).
Return to the sixth string and set down one step to C. Check the pitch against the fourth string.
Hold the fourth string by the fifth wreath, note it and adjust the open third string until both strings sound the same note (F).
Hold the third string at the fourth fret, let it note, and adjust the open second string until both strings let the same note (A).
Hold the second string at the fifth fret, let it note and adjust the open first string until both strings leave the same note (D). The guitar is now in Drop-C tuning (CGCFAD).
Tips and warnings
Guitarists who want to break out of a playing field or find a new sound can do so by changing the tuning. One of the most common alternative guitar tunings is Drop-D, where the low-E string is lowered a full step, resulting in a pattern of DADGBE. Drop-C tuning is similar to Drop-D, but with each string tuned an additional full step, where the strings from low to high are set CGCFAD.