flat
preview
your facial structure is the same in every head
you vary very little and draw to a set scheme
you stopped growing when you started drawing to a routine.
your drawing technique has not improved and your creativity is severely lacking. leading to you not experimenting.
use directional shading, you draw with straight lines and leave the lighting to create depth and features.
expand your drawing technique and you'll find that with that extra skill, and more options are available to you in terms of creativity.