Hello wenqdu! I'm sorry it's taken me a while to get back to this topic!
Your DA looks good, although I don't have any solid advice to give. Some of the anatomy is still off but your painting technique looks fine! Do you sketch out your subjects before you paint them or do you just create them while you paint?
The practice image you posted here looks pretty good, but I think you put a little too much focus on the ribs. She looks heavily emaciated and the arms seem a bit thin. It's a bit confusing because her hips and belly look fleshy, but then other aspects look very bony. That's definitely something I'd take into account. You can partially fix that by paying a little more attention to the proportions of the limbs and softening the shadows and highlights on the ribs.