Art tips?

When I first decided to join OTF, I made another forum asking for art tips. This is basically that again, but I don't feel like bumping a thread that has been dead for two+ months. I'm just wondering if anybody has any tips on shaping and shading. I'm not too worried about coloring my art unless I'm doing digital backgrounds on Magma (drawing website, i dont draw lava), since I always mess up. Still, feel free to share any tips on that as well. I've got some art below this. If it doesn't show, it's in my profile description as well. Can you tell me what I should have done better, other than shading? If so, thank you in advance!

Hamster

Bunny

Polly the Parrot(i just realized how huge the head is..)

Lion

This is from sixth grade and the wrist looks awful. Terrible, horrible, no good, very bad.

Elephant

It's fine, don't worry!

I think that they all look great! You could've shaded a few of them a little better maybe, but that's all.