I just pushed contrast with photoshop a little bit, 1 min of work. Really wanted to see how it would look, for my taste, it does need it (more black). Amazing work Marco!

In my image, I have shown the measurement of the dog and your image(didn't go full-on with analysis). It's good to go way back, back before -form- and simplify form and shapes. The lines that I have shown in the image help with orientation and observation of how big the shapes are of the subject that you wish to draw. You can use lines as 1. angles (helps with an orientation where things should be) like in the face of the dog or 2. flow like the line of the leg, belly all the way up the head of the dog, or 3. the lines of the paw, for example, can determine how tall something is what is the distance. The more you map the drawing the more you will see without even drawing lines, it will become natural and you will be able to copy almost anything it's an excellent first step in getting used to shapes and forms. But my example can be dangerous because it can put you in a safe bubble of copy-paste on the other hand it's really useful if you do not overreact with it. Hope it helps.

My recommendation would be Marc Leone on YouTube he has beautiful tutorial on perspective for beginners. (Or @Marshall Vandruff ) Then try again with robo bean. Understanding perspective is really important without it you can't find proper center of forms or bend them in space.