Hey there! I think the Hierarchy of Importance version is pretty good, though emphasizing more of the face/front area could help reinforce it as more important over the back portion of the rhino. For Light and Shadow, since the light source is coming from behind the rhino, you could darken the areas in the front, such as the face and front legs, while lightening the back lines. That way, we notice a transition from dark to light line weight as the rhino gets closer to the light, making the light source appear more defined and consistent.

It's a good breakdown and a lot of good pose studies--I like the balance between simplicity of shapes and also showing 3D form, and the general simplification appears fluid and accurate. For the imagination one, I notice a bit of a proportion change in the legs, which makes them smaller. Playing around with proportion is encouraged with imaginative sketching, though if you do, I would also recommend changing other features to balance out the exaggeration, like lengthening and tapering the neck and making the head smaller like a stylized cartoon. But if your aim is more towards realistic proportions, using other sections of the giraffe helps as a measuring system-- for instance, the leg section above the knee is about the same length as the leg underneath the knee plus the hoof. I would also recommend keeping the shape of the hooves simplified (like in your studies) for your initial lay-in, before diving into more detail. And lastly, one more suggestion is that the knee of the giraffe should bend backwards rather than forward, if, again, your aim is realism. I encourage you to try out different poses from imagination as well, as this can help develop more fluidity and confidence when it comes to sketching, and help you gain momentum as you become more familiar with your subject--plus it should be fun :) Hope this helps!

Hey Henrique, beginner here as well, I'll tell you what I can spot: Yes cast shadow is a bit too short and perhaps the darkest shadow of the pear is a bit narrow, or too light? Keep up the good work!

I'm only going to comment on the pear since I'm a beginner. I think you did a great job with simplification and area distinguishing on the pear.