Originally found at this link.
Tips, Tricks and General Info for Dear Mary Sue
Is it a Mary Sue or not?
So you've written a fic with your own character and now you're wondering if it classifies as a Mary Sue or not... Well, if you're actually at the point of wondering then the odds are in favor of Mary Sue. Come on, you may be your worst critic but you're also as blind as a bat when it comes to judging your own ideas. This basically means that if you've actually gone ahead and written it you obviously thought it was a good idea... and it will either take time or a lot of flak to make you realize that maybe your good idea really sux...
Mary Sues tend to either A) just appear out of nowhere..... or B) are related in someway to one of the established characters. There are a couple of other ways to introduce them but those two tend to be the norm. This doesn't mean ALL characters introduced as such are Mary Sues, but the majority of them are, due to turning out to be a made-up relative or love interest to a series character.
The qualities of a Mary Sue:
By her very nature, Mary Sue is a drama queen. She will take up or appear in 75% or MORE of the fanfic.
She will capture the attention of at least one of the other characters... possibly even more...
She will either be a genius, a black belt, the best shot this side of the Wild West, will always know what to say, will always know what to do, and/or will look like god's gift to mankind... This behavior is rarely explained... and even when it is, the reader is usually too annoyed by then to care.
She will either be the main reason for the plot... a large portion of the plot will belong to her... or she'll be the one to keep the plot chugging along.
NOW ... that's not to say there aren't any good Mary Sues out there... there are. But they are shining little gems sprawled out amongst all of the mediocre stuff. Basically, if you ever FIND a good one... treasure it because you probably won't see another one for a very looooooooooong time.
But, if you actually want to add to the piles of Mary Sues out there and you don't want it to suck... here's a formula that might help:
Keep your Mary Sue's appearances in the fic down to a bare minimum... more along the lines of 'out of site... but not out of mind'.
If you're going to give your Mary Sue scenes of her own... try to keep them small and infrequent... it's much better to have your Mary Sue interacting with the other characters than just on her own.
Describe her well... but don't go overboard. Describing how she looks when she shows up for the first time is a must... but don't rehash it in every freakin chapter.
Try to get her to interact with the other characters... as opposed to her just telling them stuff for the plot and/or telling them what to do next... Remember, don't let her be the focus of the plot or the one to move it along... ect ect.
Try to make her into a person that the readers will like... or least somebody we can sympathize with.
Other than that, good luck... you're gonna need it. :o)
Mary Sue Page