Your "lizard thing" has no depth it looks very flat right now. Use your colors to show thickness in the body instead of trying to use it to color the skin. While the arm anatomy is not right it still has a much nicer form than the legs. Right now it looks like you got tired and threw the legs on real quick. Take out all of the dark green lines and highlights that are used like lines and draw in the forms and give them shape before you move on to anything else. It seems you started doing it on the abs now you need to continue that on the rest of the body. Pick your light source and start giving highlights to points close to your light and then dark shades to the areas hidden from the light. Check out some references on anatomy and it will help it look more coherent, there are some links in the resources thread in the general section.
