The don'ts of making an OC

Character Personality

Now that you know how to get the backstory right, let's get started on character personalities!
-Give your character some flaws. Yeah, it'd be cool to have everybody like you and to have no insecurities, flaws, or problems, but it's Mary Sueish. You NEVER want to make a Mary Sue character unless they're the enemy, and even then you should at least give them SOME flaws so that your character can use SOMETHING against them.
Now, don't make your character TOTALLY flawed. Just give them a few flaws and insecurities so that the audience can relate, and so that they can actually stand the character for more than 5 minutes.
-Don't make your character too modest. This is REALLY Mary Sueish. Modest characters are characters who deny compliments, like if someone says your character is beautiful and your character just responds with "thanks but you have this wrong. I'M not the beautiful one" even though they KNOW they are. It's not really "normal" behavior. Normal behavior is just a simple "thank you!" or, since were so self absorbed most of the time, maybe even "I know, right!?"
-Don't make your OC complain too much. This is pretty self explanatory. It just gets grating after a little while.
Okay, now let's move on!