BG- Your drawing is good. You are doing a great job of breaking the form into light and shadow, the line quality in the hair is nice. You obviously understand the shapes and forms that you are rendering.
One way to strengthen your drawing is to visualize the major relationships. Everything relates to everything else: its size, position, and angle are all relative to the other elements of the drawing. The more of these relationships that you can identify and establish, the more ?solid? your drawings will become.
A great tip given to me by one of my instructors is to look for the ?enclosures? ? every solid form has opposing ?sides? that form an enclosure.
The enclosures can be parallel: | |, they can form an envelope: / \, and they are not always visually directly across from one another ? they can be offset.
If you get these major relationships accurately, the drawing will ?read? well, even without details of the individual features. These are the relationships that establish the overall shapes of the major body masses. This is what you identify when you recognize someone from far away. These give the body its general ?character?. The smaller relationships determine more specific characteristics, but without the establishment of the larger relationships, they are not strong enough to ?carry? the drawing.
Here is the photo of Corinna standing, with notations for some of the various major enclosures
For instance, when you are looking at a torso from the front, the left and right side of the ribcage form an ?enclosure?(See lines A.) Once you have located the largest enclosures, then you can refine it further (See lines 1 ? 3.) Do the same with forms such as the pelvic area (lines 4 ? 5) and the legs (lines 6 ? 7.) You can take this approach as far as you want. Sometimes it gets ?interesting? like the enclosures of the muscles on the arms. Just remember, every left side has a right side, every front has a back ? even when it is hidden behind another object, or when it blends into another muscle.
One more thing to recognize is that the spine is rarely going to be directly in the center of the ribcage. Usually, the model is turned or tilted toward or away from your point of view, making the distance from the spine to the left edge (3a) different than the distance from the spine to the right edge (3b.)
When I am looking at my drawing and wondering why it doesn?t ?seem right? even though the details are rendered well, I can usually find a major relationship that could use some adjustment. For instance in my drawing, the left arm is a little too ?thick? compared to the right arm, and the space between the bottom of the chin and the top of the shoulder needs to be increased. Overall, the drawing is a bit thick; it could stand to be longer and narrow. Quite often, it is the more ?general? elements that make the difference; they are subtle and sometimes elusive.
I found that as I paid more and more attention to the larger relationships, my drawings ?read? better, even before the placement of details and rendering. Seeing these relationships should help you, too, no matter what approach or methods you use.
I hope this is helpful.