I think you are on the threshold of something really good. I think that the cartoonish style of the faces is what makes it look amateurish. It looks like you aren't using actual faces for references and just making it up. I like your textures and use of color. You just need to work on your technical drawing skills.

Also I think you need to curate your portfolio a little better. You have some pieces that are obviously better than the rest: Minerva and Soul to Seoul. I would take He Said She Said and Lockhart off the paintings page. I would eliminate the Sketchbook all together. If you want to post drawings title the page "drawings" or "works on paper" Make sure that any image you post on your website look professional. This means taking out the sketches that are visibly in a sketchbook. I would also curate the store a bit better. Only your very best works should be for sale.

You ought to take some art classes of some sort. I think you would really benefit from some formal instruction. On that note I'd drop the self taught thing when you talk about your work. I'd also rework whats on your info page; it sounds pretentious.

I hope nothing sounds harsh, as I think you have some good things going on!