I think this is more a question of graphic design but from composition pov you could apply a trick often used in comics where elements (objects, shadows) and (motion) lines point toward the main subject. The ground could use more visual interest. I added pieces of cheese as an example since the drawing has a mouse but it could be anything that would fit the character's story. For letters I would try to play with negative space and patterns to keep it subtle but still interesting enough to look at. Try to avoid using white color for background unless you absolutely want the viewer to focus on that particular part. Rule of the thumb - the brighter the color is, the more attention it steals. The color combination is pretty good, though - just needs few tweaks. Good luck! | Artwod Feedback