These turned out pretty well!! You're really selling the front edge line weight in that first drawing. One thing to assess a couple times throughout the drawing is whether our line weights are consistent with what we want to say. It seems that your rhino horn and legs are heavier to imply closeness. But the the neck between the horn and leg has a much thinner line weight so it makes it feel a bit more like the thick line is stylization, rather than being about the depth. I noted that are in blue. Another thing you can do to really push that depth is to have the overlapping areas change in line weight like in the humps of the back and where the font legs overlap the things behind them. You're off to a great start and seem to be NAILING your proportions. Keep at it and share your work more!