The biggest tip-off that Anita Blake was a Mary Sue was the fact that Anita looks like an idealized version of the author: Tiny, very pale, dark curly/frizzy hair, dark eyes. Then there's the "can do no wrong" feature, every character who tells Anita she's out of line gets killed off or beaten down. And let's not forget the whole thing with her ex-husband/Richard and her then-boyfriend-now-husband/Jean-Claude.
Bah. It's nauseating.