When no one is looking, they break the rules and push the limits. When caught, as inevitably they are, they may lie or rationalize or seek to hide the evidence.
Treat that child with sincere love and dignity, but require him or her to follow your leadership. Choose carefully the matters that are worthy of confrontation, then accept her challenge on those issues and win decisively. Reward every positive, cooperative gesture she makes by offering your attention, affection, and verbal praise.
Nearly three times as many strong-willed children made Ds and Fs during the last two years of high school as did compliant children.
Someone reminded me recently that the same boiling water that softens the carrot also hardens the egg.