I'd say you need some comment!
Well, I'd like to say, I like the variety of different kinds of artwork you make! Since I'm more familiar with GIMP and hand drawings, I took a look at those for a bit. =]
I'd have to say, I like the "Autumn colored Simisage" the most. I like the orange color and I think the line-art is much neater. The shading was okay, but the shading on the head, face, and legs made it unclear to me where the light source was coming from. I'd watch out for that! Why? It's less confusing where the lighting is coming from and it looks so much neater and better. Trust me! =] If you really need help on how to shade better, I'd just study normal objects around your room and see the different shadows an object has because of the lighting. Outside is good, too.
Sorry for not having a fantastic/awesome doodle, but you'll understand here where the source for the highlights are. From the angle, shading and highlighting, the Mudkip looks somewhat three-dimensional. You can tell pretty well where the light source is coming from. Once you get the basics of that, you can expand to other kinds of light sources in different angles.
Other than shading, I'd try to be a little neater on the line artwork. Erase some lines here and there, and try to make lines with one stroke if you slowly draw your outlines. If you draw a line quicker and in one stroke, it looks a lot neater than slowly building up that line.
I like to warm up by drawing more than 50 circles, very fast! All of them drawn with one stroke. It helps to draw much better, less bumpy lines and circles. ^..^
Uh, if I can think of any other advice, I'd maybe play around with colors more? To made set a mood or show what time of the day it is in your drawings. You have some nice work, and I hope I somewhat helped you out!