To act 'according to one’s strength' means to use a little less than necessary both of food, and drink, and sleep... As for food, restrain yourself when you wish to eat a little more, and in this way you will always make use of it moderately.
As soon as you wake up in the morning, pray for a while, saying: 'Lord Jesus Christ, Son of God, have mercy upon me.' Then your first work should be to shut yourself in your own heart, as if taking up position in an arena. Having established yourself there, bring yourself to the consciousness and feeling that your enemy and the passionate urge against which you struggle at the moment are already there, on your left, ready for immediate attack; therefore rouse against them a firm resolve to conquer or die, but never to submit. Realize also that on your right there stands, invisibly present, your Commander, our Lord Jesus Christ, with His Holy Mother and a host of holy Angels, with Archangel Michael at their head, ready to come to your aid. So take heart and be of good cheer.
Concerning fasting, do not grieve, as I have said to you before: God does not demand of anyone labors beyond his strength. And indeed, what is fasting if not a punishment of the body in order to humble a healthy body and make it infirm for passions, according to the word of the Apostle: 'When I am weak, then am I strong' (II Corinthians 12:10).
When anyone is disturbed or saddened under the pretext of a good and soul-profiting matter, and is angered against his neighbor, it is evident that this is not according to God: for everything that is of God is peaceful and useful and leads a man to humility and to judging himself.
Do not judge and do not belittle anyone, because from this the heart grows faint and the mind is blinded, and from this, negligence appears and unfeelingness of heart is born. Keep ceaseless vigil, learning in the law of God, for through this the heart is warmed by heavenly fire, as is said: 'In my meditation a fire was kindled.'
If the Lord delays granting you full victory over your enemies and puts it off to the last day of your life, you must know that He does this for your own good; so long as you do not retreat or cease to struggle wholeheartedly. Even if you are wounded in battle, do not lay down your arms and turn to flight. Keep only one thing in your mind and intention - to fight with all courage and ardor, since it is unavoidable. No man can escape this warfare, either in life or in death. And he who does not fight to overcome his passions and his enemies will inevitably be taken prisoner, either here or yonder, and delivered to death.
Let us have recourse to humility on all occasions; for the humble lie prone on the ground, and how can a man fall if he lies on the ground? But a man who stands on a height can easily fall.
My brother, the passions are afflictions; and so the Lord does not excommunicate us because of them, but He says: 'Call upon me in the time of affliction; and I will deliver thee, and thou shalt glorify me'. Therefore, when beset by any kind of passion, there is nothing more useful than to call upon the Name of God. All we can do, weak as we are, is to flee for refuge to the Name of Jesus. For the passions, being demons, retreat if this Name is invoked.
But a sober and prudent man who desires to be saved, when he sees from what it is that he suffers harm, carefully preserves himself from evil remembrances, is not drawn into passionate thoughts, avoids meetings and conversations with those for whom he feels attraction and avoids every occasion for sin, fearing lest he himself ignite a fire within himself. This is the warfare which proceeds from one’s own lust, which a man brings on himself
Looking at yourself or at other people and thinking that you alone have been given high rank, that you alone of all living beings on earth have the gift of reason, and serve as the point of union and connection between material and immaterial creatures, rouse yourself to glorify and thank your God and Creator, and say: 'O eternal Trinity, Father, Son and Holy Spirit! Be Thou blessed forever! How greatly must I give Thee thanks at all times, not only because Thou hast created me out of earth and hast made me King over all earthly creatures, not only because Thou hast honored my nature with Thy likeness, with reason, speech and a living body, but above all because Thou hast given me the power, of my own free will, through virtues to resemble Thee, that thereby I may possess Thee in me and rejoice in Thee forever!
Silence of lips is better and more wonderful than any edifying conversation. Strive to acquire humility and submissiveness. Never insist that anything should be according to your will, for this gives birth to anger. Do not judge or humiliate anyone, for this gives birth to anger. Do not judge or humiliate anyone, for this exhausts the heart and blinds the mind, and thereon leads to negligence and makes the heart unfeeling.
Pre-eminence belongs to the Jesus prayer because it unites the soul with our Lord Jesus, and the Lord Jesus is the only door to union with God, which is the aim of prayer.
When you intend to do something and see that your thought is perturbed, and if after invoking God's Name it remains perturbed even by a hair's breadth, know from this that the action you mean to commit is from the evil one and refrain from commiting it. For nothing done with perturbation is pleasing to God.
Give thanks to God for all things, because thanksgiving is intercession before God for our weakness. Judge yourself always and in everything as a sinner and as one seduced - and so God will not judge you; be humble in everything and you will receive grace.