From the Painting Guide: You're obviously well bitten by the painting bug ... and fortunately there's no cure for it! Keep trying out the different mediums available. Each gives a different effect and works in a different way. And don't forget that mixing your mediums is an option too!

Things to consider:
Capturing 3-d on a 2-d surface: The eagle and the dog are a bit two-dimensional, they're a flattened out rather than having a strong sense of curving around the body of the eagle/dog. An exercise for working on the shading that creates this is to take a simple 3-dimensional object such as a box, can, apple or ball and look at the shading. Do some monochrome sketches of this. A monochrome or solid background, such as the blue on the eagle, will also contribute to the feeling of flatness."