You have one but very important problem. Make your outlines more solid. Yours are semi transparent and fuzzy. If you like the result its fine but I promise you if you can use layers make a sketch layer than a solid line work layer than start coloring. Also if you change the color of the line work depending on what your coloring that will make so mulch more definition in your work. Look up no game no life. They use red outlines for everything and its very nice.