Notice that to gauge the width of the nose and mouth, I draw a rough triangular shape from the bridge of the nose.
I always go for uncomplicated shapes when drawing the hair. If I try anything too complicated, initially, it always goes wrong.
With all the workings out still prominent, face is not looking attractive and o bit on the harsh side.
Remove the guidelines and begin to soften the features , making the eyes, nose and mouth prominent. Notice that I have reduced the amount of lines for the nose. I often find going too heavy with the line work for the nose can often age the look of the character.
I adjusted the curves of the hair to what feels right to the eye. Well, my eye, at least.
I learned about keeping the hair simple form watching Disney cartoons,
and later , by studying Bruce Timm's work.
Once you feel confident arranging the components that make up the face, try capturing other ethnicity's by adjusting the eyes, nose and mouth, and jawline.
Another way of looking at constructing the human head is by using a sphere/ball shape and a cube.
As I mentioned earlier, I keep to simple , uncomplicated shapes for the hair.
This is how I generally approach drawing the human head, but you don't have to take this as the only approach, there are plenty of books out there, for example: