Very cute.. And good job on your first pic!!! Some suggestions would be for you to use layers in order to perfect and straigten lineart... On one layer, sketch out (using the pen tool or pencil tool) what exactly you want to draw in a very rough form... Then, on a layer on top of that, run over the necessary lines so that you can systematically erase the lower layer with the rough copy of your work... Then use different layers to color... Just some suggestions:)