Hey Natali, These are pretty good, your gestures are quite nice. When you start to add structure though, you want to think more about perspective. This will help your drawings look more 3D. I did a couple of drawings to show you what I mean, I hope it helps :)

Hi Natali, when drawing shoulders and pelvis, regardless of whether you are drawing a human figure or an animal, I recommend using boxes instead od curved formes. That will help you to set le limbs in an easiest way and to read the prospective and the position in the space. You actually did that in the salamander quite well. Horses, for example, have a lot of squared shapes they have a little amount of fat, very strong muscles and lean libs where you can clarly see bones and tendins. When i draw an horse I always start searching for the spine, then i construct the boxes of pelvis and shoulders, then there is the oval shape of the rib cages and the spike of the head and simples curved lines for the legs. On this structure i build the horse but is the same process for any figure :)