The first step along the way to playing quartertones is learning to hear and feel the distance between the intervals. This takes time and practice, because it is all too easy to become disoriented with regards to the center of pitch.
For this reason it is very useful to play an open-string drone so that you begin to hear the difference between the “normal” intervals that you’re accustomed to and the “in-between” intervals of the quartertones. The exercises below do just that:
Exercise 1 works gradually up the A-string, using the D-string to help you check your intonation and stay on track.
Note: You should try the above exercises using all combinations of strings!
This is only the beginning! For more exercises, read on: Quartertones: More Practice