If anyone wants to drive out the demons, he must first subdue the passions, for he will banish the demon of the passion which he has mastered. For example, the devil accompanies anger; so it you control your anger, the devil of anger will be banished. And so it is with each of the passions.
Fasting needn't be limited to abstinence from food alone, because true fasting is departure from evil deeds. Forgive your neighbor any insult, abstain from causing your neighbor offence, abstain from irritation, from senseless sorrows, from fear, wrath, and so on. ‘True fasting is alienation from evil, temperance of the tongue, setting aside of wrath, casting out of lust, idle talk, lies, and oath-breaking’…This is a true and pleasing fast for the Lord. Departing from these vices and from a corrupt state is what comprises a true fast.
When it is painful to remember the past, it is better to simply repent of what had been bad, and think no more about it. In order not to despair or be enfeebled by it, 'remember the examples of God's great mercies to great sinners. The main thing: do not condemn, do not envy, know yourself and be with God.'