Ok, this is drawn good, not spectacular, but good. I find 2 'problems' if you will.
One problem is that, as a whole, it seems like you didn't compare the tones. What I am saying is that you went in, as carefully as you could, to find shapes of light areas, halftone areas and shadow areas and filled them with tone. This would have worked but you haven't compared all these areas correctly to each other.
For instance, look at the breasts. The one on the right is lit, it gives the information as to where the light is coming from, it has a shadow area and even casts a shadow. Regardless if the values and their relationships on the left breast are good or correct, they have a feel for the light. Now, compare this to the breast on the right. It looks almost as if it is a lightscource itself. Sure there will be plenty of light on one side, but the shadow side is very light, and although it could have been reflected light, or a second light source, why doesn't it affecting anything else but the right breast?
What I am getting at is, that each part may be rendered well, but in comparison to each other in the whole image, there are issues. If you don't compare the whole, it will not convince the eye, be it realistic or abstract.
This brings me to the second 'fault'. This is based on a hunch I am getting from looking at the image, so I may be wrong but regardless it's good to say, because it binds with the previous one. You seem to have not looked for planes of light. Instead it seems like you were copying (as I said before) 2d shapes.
Now, what is bad about this is that when we do this it's like drawing by the numbers. Space 1 has this tone, space 2 the other tone. We tend to forget that we are studying the light on the object and the objects' threedimensional character, or volume. The consequence of this is that we forget to see big volumes and make them stand out.
For instance, the area of the hips. It is basically a big box, this area. Looking at the art I am supposed to feel the sides of this 'box'. Only if the image is very graphic (like a 2 tone piece) will this be an issue, but here you have a full range of tones, and you aren't using it. I look at the left and right sides of the hips, and I cannot see, understand or feel the 'sides' of the hips, I cannot see the form go around. I see the front side clearly, and there is a good seperation of light from dark, but that's it. I cannot see any 'core' shadow at any point, the abs, the hipbone or somewhere else, to indicate that the form turns inward. you might argue that that was the way it was lit, but still, if you look at it more closely, you will see the big basic tones giving the feel for the sides, their tonal difference may be small but it's there, you should show it, and you must decide upon showing this difference by either using a small difference of tones in a large area (and ignore the small nuances of the form) or exagerrate the difference (and then change the tones of everything so as to have ballance). On the light side you have saved it a little. On the other hand it has worked nicely on the neck, the arm to our right and at the pubic area.
Instead of drawing things so 'carefully' (I don't mean that you should ignore good drawing) go for good solid big volumes where you can feel the 3-d quality and then start cutting to smaller forms, it will be better (and faster). There is no mean in you showing us the shadow in the abs if we cannot feel the volume of the whole.
Don't feel that your piece isn't good, it is. It very good, but it has small errors that shouldn't be there for your level so it's best to eliminate these now.
Nice start to it. I agree with all that Line said. I only recently sort of got that eureka day when i was watching this video on figure drawing. The teacher was explaining how to go from big form modeling to smaller form modeling. As explained by Line, first look at the big form because it is the big form that matters, that give the picture its solidarity. Example, i suspect from ur image that the light source is at your top left? So if u consider your torso to be a egg, tehre will be a spherical gradation expanding from the point of highlight (hard to explain, i hope u understand). so generally each of the light area will have a "average value" So with that value in mind, when u move into the small form modeling, u must still maintain that overal value relationship. If you consider the two breasts, if u imagine the "egg", the right breast should be lower in value than the left, so the max value there will never be higher than that of the left one. In this way, u can retain the value relatinoship.
Think i am kinda crappy in explaining..... haa..
"Choose only one master.. Nature. " Rembrandt
"The only time I feel alive is when I'm painting." Van Gogh
Wow thank you for such an in-depth response, this is my first drawing that I've ever done to such a high degree over multiple sittings. I'm going to take sometime this weekend and definitely work on unifying the form as a whole and better defining the core shadows.