There are actually many ways to get nice-looking effects on MS Paint. For example, try using the Spraypaint tool to get fades / flames / clouds. (Maybe I should write a guide to some of the few effects I know. xD)
Judging from the title, I thought this was going to be a strictly Paint-only banner, but I guess you incorporated things that weren't done in paint... Anyways, it looks... Well, the background could use a lot of work. I know the spraypaint tool would have been fastastic for that, or even just a color fade made from gradually choosing lighter colors and using the line tool / pencil tool.