O_O;
Too be quite honest, they all lack in basic creativity and structure. You should definitely work on your framework. For example, Razorleaf looks like something a 3rd grader drew. It has close to no expression whatsoever, as a matter of fact, it looks like its a subdivision of the undead; its legs are ill-proportioned because the tibia and fibula are much longer than the humerus as they shouldn't be, the fingers and toes look as though they were bits of discarded seaweed pasted to the hands and feet, and the tail is just unsightly.
I highly suggest that you start practicing by replicating pictures of animals, such as: dinosaurs, four-legged animals (dogs, cats, ect.), bipeds, and insects, to aid you with your anatomical problems. Try doing practice sketches before you decide on a final form (I suggest maybe 5 at the most). Also, you may want to copy pictures from other animes withing the monster genre too help you with some ideas and to get your creative mojo flowing.
Your shading is okay, a little mediocre, but not bad. You outlines are scratchy and messy; I highly suggest that you practice getting them smoothed out, which I'm sure that you could do in Photoshop or PSP using erode, the line tool, or edge preserving smooth.
Overall, not your best, I'm sure. Just keep working and sharpening your skills. By the way, what program did you use? It looks like you used Paint, although I just want to be sure.
Psycho