Where can I learn to draw weird little creatures?
The first thing to do is to draw lines like he does. His vary in thickness, thinning towards the edges. Yours, at least in your link, are sketchier and more uniform. This is a small but very significant difference. If you draw on the computer, a pressure sensitive pen and a the proper drawing software will make this part easy. The second element is the watercolor was for the shadows. Again, a computer program like Painter makes this trivial. Paint faintly behind your outline, with low opacity. Paint again to darken. Use a smaller brush than you think is necessary. Then just be creative, develop the character of what you’re doing, and practice practice practice.