How did I do?

I recently did my first animation and this is one of the result. I'm really enjoying it since it feels like a different skill from just making an illustration. They said that everyone should start with a bouncing ball so I did that. Any advice you can give me is highly appreciated. They said that I should keep in mind the volume of the shape but I don't know how to do that. I'm really having fun in doing this, and I wish to learn more!