☢ How NOT To Create a Mary-Sue ☢
Generally: when in doubt, ask a more experienced writer.
(^Keep that in mind when you're stumped)
This is a guide for those who prefers to avoid a Mary Sue/Gary Stu, or doesn't know how to make a non-Sue and is craving for advice. Well, here you go. It might not be perfect, but its worth it to save your writing skills and satisfy your fans.
But just remember- just because a person hates Mary Sues doesn't mean their characters are automatically non Sues. More on that later.
"What is a Mary Sue anyway? And why do people create them?"
So. Mary Sues are usually defined to be "overall perfect characters with far too minor flaws, having illogical powers and traits, lacking personality and usually being fulfillments the fantasies of the author". This is quite correct but also rather blunt definition. Many, many Mary Sue creators (also known as Suethors) have heard of this definition and even say they hate Sues, but still they do Sues. So, they can't recognize that there is something wrong with their characters, and they can get even fiery when someone notes about the issue. Why?
The problem can consist of the following issues:
1) They don't have exact image about what is exactly a Sue, or the image is very black 'n white. I have met some people that claimed that their characters aren't Sues, because the characters are not OVERALL PERFECT - they had this and that minor flaws that appeared in the character's info sheet but not in the stories. Not talking about those TURBOBOOSTÃœBERPOWAAAHS the characters had and which weren't balanced with reasonable weaknesses. The creators believed that minor cracks is enough to make their characters non-Sues; which wasn't, sadly, true. I hope this tutorial can declare you better what is a Sue than how they understood.
2) The creator grows too attached to his/her character that (s)he can't see the character is slipping to the Sueness. The best cure to that is to show the character to ADULT and EXPERIENCED writer and ask what he/she honestly thinks about the character. Prefer to ask not-so close people instead of your closest friends and such: friends are often afraid to upset you if they note something gravely bad in your character, and they can also empathize you so much that they can be biased.
It's best to offer the critic a written piece about your character's story in addition to the character sheet, or at least portrayal about what is the world where the character lives. At least I have difficulties with evaluating if a character is a Sue or not if I see only the character sheet without a context.
Also, attachment problem can be partially prevented by making the character distant enough from the author. More in the tutorial.
3) The creator is trying to create "something cool" and fails in understanding so-called "Rules of Coolness" (as lacking the better name). This is easier to understand with some experience, but to put short: usually, young/inexperienced character creators (but, usually the very young ones) tend to think that the more super powers the character has, the prettier (s)he is and the more awesome personality (s)he has, the better character is. Like a small child decorating a cake with heaps of sprinkles and buttercream, that much that they are running over the cake.
However, this may not always work.
Think again: Do you REALLY want to create a character that has no excitement in his/her life? Why should (s)he has uber awsum powers for every single problem while you can make more excitement by making him to worry, "Damn! There is a problem, how to solve it before cannibals come to eat me?" Or the personality? If we can ALWAYS assume that your character is always right and never makes mistakes... well, there is no room for the character development, and THAT'S utterly boring.
Ask yourself what you want to read when reading a story belonging to the genre of which you are writing. You probably start to think about issues like excitement, humor, sappy romance etc. Well, let's stick on the excitement. What causes excitement? Being not able to predict exactly what happens next. Surprises. Taste of danger and lingering "oh s**t how can I survive" feeling. Jumping into the hero(ine)'s shoes and feeling the adrenaline in his/her veins. THAT'S IT. Don't make stuff too easy for the hero(ine), otherwise the readers lose the excitement!
After that blabbering, to the guide itself!