So first of all, very nice job! Stop selling yourself short! 
I think you’re probably looking for more detail… more contrast between your subject and its background. Yes?
Well, I’ll tell ya… When I did my Harry Potter coasters I spent hours in PhotoShop getting what I wanted out of the artwork I found on the internet. I boosted up the contrast on each one, added a thin black line around each subject part so it stood out from the background, and generally played with brightness and contrast until I got what I thought I wanted. As far as I’m concerned, it worked out really well. Worth the effort? Well, yeah, since they were a wedding gift for my cousin. My point? You CAN get it the way you want. But you really have to work with some images. Some will certainly be considerably easier.