I would like to improve my art in general. I am self-taught.
Yowza, Verati! Yowza on the inner feelings of your model. I love how well communicated your pose and expression are.
Well, if I was to give you a completely and totally honest critique, it would be that this expression is a bit too stiff, especially the hands. Why don't you please loosen up the cartooning and the drawing with 156 minutes of 30 second theraputic warm-ups of hands and faces and expressions? (156 x 60/30/2 days, 9360/30/2 d, 312/2=156 sketches a day)
The reason why you could and would do this trick is because of the Will Finn podcast on Pencil Pushers, he said that he said that capturing the gestures is extremely important, because if you'd do a long study, it would be absolutely rigid, but if you'd do a 5 second study, you'd get the best result possible.
Cheers to you, and good luck on your goal.