Hope this isn't sound weird but when you are creating a work of art. What do you try to accomplish with each piece you create. Do you hope to learn or have you learned something new artistically with every endeavor? (Two questions, I know, my bad!)
All I do is draw poses of naked women, am I consciously trying to accomplish anything? The answer is NO.
I do hope and want to learn but I don't approach it from that end. Mostly, I want to enjoy drawing the form, it really is a lot of fun to draw women in the nude, it makes me warm all over.
I know through previous experiences that the best way for me to learn is to draw really fast, pose after pose, after pose and so forth. I can't quantify the learning. I don't know how much I'm learning or if I'm learning anything at all; all I can feel is a sense of orientation in regards to my position within the the female body as if it were the map of city with landmarks, I don't know what the names of the streets are, I just know I am not lost. Likewise, I don't know the names of all the bones and muscles —just the most prominent ones— but I definitely know where everything is and the shapes they adopt given a particular light source or pose.
I tend to subconsciously choose what I consider challenging poses (at least for me they are) Poses that offer an opportunity to draw the things I have problems with.
For instance: since I have trouble drawing hands I would pick a lot of poses where hands are prominently displayed, not hidden behind the back of the head and such. So I go after them with vigor, sketching mad like it's 1999.
Like I said earlier, I don't know if I'm making immediate progress but with each new drawing I feel more and more comfortable as if I know my way around a city that once felt totally foreign to me.