If I begin feeling a character is coming up this way, I like to find one of the many "Mary Sue" tests available on the web. Then I alter a few things that will make the character score better (i.e., less of a Mary Sue / Marty Stu.)
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Regards,
Eric Fretheim
Assistant Prep Leader, 2015 October NaNoWriMo Prep Challenge

"It is perfectly okay to write garbage-- as long as you edit brilliantly." ~C.J. Cherryh

“No, writing 50,000 words in a month is normal. You are not crazy. This is not insane.” ~Teri Brown