Image from Giphy.com. Shot of Usopp from One Piece.
Give Them a Flaw
While this technically could fall underneath the previous step, it is so important that it is worth a step all its own. Create a flawed character, no matter how incredible that character is.
Superman has his kryptonite, but he also acts with a flawed veteran instinct, an insecure feeling of having no effect on the world, and sometimes the inability to hear the voice of reason. Consider, as the creators of Superman do, what a character’s positive aspects are, and what negative flaws could exist because of those aspects.
Obviously, flaws can come from anything, but if your character’s flaw says “too awesome,” then, unless you plan to make good on that promise and make that a flaw, you need to restart from Step 6.
In fact, the more detailed your character, go ahead and repeat Steps 6 and 7 as many times as you want until you are ready to continue.