Murdering Mary Sue

Remember, having Sue traits doesn't always mean your character is bad. Context and how the character is written are important! You can't have a character blurb with all the potentially dangerous traits listed and expect someone to be able to tell whether or not it's a Mary Sue/Gary Stu. Writing well is far more complicated than that.

If you are worried about your character, trust your gut instinct and get someone you know will be objective to review your story, not just the character alone.