Nice to see some drawings in this forum
since most people here excel in making stories and graphic designs
I gotta say that I really like your art a lot.
as for the criticism... hm.... I think I also agree with the others that the proportions of the characters could use more works for sure
there are many tutorials available out there, and do you draw with using sketches? (like making the skeleton model first, etc.) if you don't then you should try since I think it helps quite a lot
Aside from the proportion problem, I see your art as "daring"
You can do dynamic poses and they turned out really well. As for the BG themselves. I see no problems at all. They're simple yet great. And looks like you could make the complex one as well (that bedroom pic). My favorite is your Sayaka pic. Very impressive lighting done over there ^^ (Oh, yes. I see that your lighting and shading are also your strong points).
I do some drawings too, but too bad I'm still struggling with the coloring
I don't have a tablet pen~ XD