This sounds like a good start. For shading practice, you could use some exercises from Proko or watch some free lessons on YouTube. (https://www.youtube.com/watch?v=TfAZt3O0sLY), (https://www.youtube.com/watch?v=t1Oy4EYjlT8) I'm currently studying shading and rendering as well. I'm challenged by transitioning from using lines to focusing on edges in painting. Right now, I'm doing studies on painting basic forms and understanding how light interacts with them. I like your color palette in your paintings. One thing that stands out to me is that all of your pictures are very straight-on. If you adjust the perspective slightly to the side, you could create more visual interest. I hope this was helpful. Enjoy your painting journey!

Are there specific areas where you want to improve? Do you have any particular topics you'd like to study further or any challenges you're currently facing? This might make the feedback more valuable to you.

Do you have the references for these? I see that you are trying to group your values, but your edges are not helping, and some transitions are kind of harsh. if you provide the references I could help a bit with painting over your images.