I'd say clean it up and ink it. Best way I've come across to clean up images before coloring and inking is A)Tracing paper, but the paper itself is kind of flimsy and bothersome at times, but it is the easiest and possibly cheapest way. B)Vellum, you can buy entire reams of vellum at scrapbook stores and it can be dead useful, the only thing is that you have to have a steady hand when tracing it, because if you erase on vellum it'll turn up really messy on a scan or photograph. C) I use the glass coffee table that I've got, and a camping light, and then create a make shift tracing table. If you've got the glass table, I really suggest this one.
Past that, if you want to keep it messy (and it is sort of endearing this way - reminds me in a good way of old school anime style) then I don't see anything that you could add. The composition is a little unbalanced, imo, but you said that you added the girl in later, and so it's not something you can really help. Good work, I really appreciate and enjoy your art style biggrin
