I'll admit that I definitely agree with skedad. I wouldn't dream of doing any work from scratch in MS Paint, simply because of how tricky it is to change later. Overall, I'd suggest finding yourself a much nicer drawing package, such as Inkscape (which is open source software) or investing in a pricier (i.e. not free) programme if you find yourself doing a lot of editing. From personal experience, I love Inkscape for both its simplicity and, at the same time, complexity of features. It's got enough to let you do a lot with it, while not so much you're swamped with options as a beginner. Not a bad little vector graphics editor, really.

Overall, though, I'm trying to suggest people use pretty much anything than MS Paint, as for vaguely professional work there's more than enough far superior programs out there.