Pope Shenouda III
Take your point of weakness and make it the topic of your prayers and the target of your efforts during your fast.
Concentrate fully to be careful and exacting and in resisting it.
Pour yourself before God, and say to Him: Save me, O’ Lord, from this sin. I admit my weakness in this particular case and will not conquer it without Your help. Have mercy, O’Lord, on my weakness and helplessness. I do not want to conclude this fast before this sin is eradicated from my life.4
Collect Bible verses that deal with this sin. Place them before you so that you may read them constantly.
Let fasting be a period of struggle with God so that he may grant you fortitude to conquer your sins. Train yourself while fasting in this kind of struggle, and say: Since, according to the Lord's words, fasting exorcises the evil ones, may it exorcise the devils that wars within me with the sins with which I am weak. May it exorcise my sins as it exorcised devils when coupled with prayer.