The Holy Fathers teach us how to become familiar with the Gospel, how to read it and how to understand it, what helps and what opposes its understanding. Therefore, at first you must devote more time to reading the Holy Fathers...
Pray simply. Do not expect to find in your heart any remarkable gift of prayer. Consider yourself unworthy of it. Then you will find peace. Use the empty cold dryness of your prayer as food for your humility. Repeat constantly: I am not worthy; Lord, I am not worthy! But say it calmly; without agitation.
Remember that a good action is always either preceded or followed by temptations. God permits this so that the virtue, exercised in that particular action, may be confirmed, consolidated, steeled.
When God, using our conscience, calls us to righteousness and yet our self-will opposes Him, He respects our freedom and lets our own will be done; but then, alas, our minds grow dull, our will slack, and we commit iniquities without number. On the other hand, the fruits of the spirit are soon granted to them who follow the commandments of Christ our Lord.
Most people desire and seek after prosperity in this life, and they strive to avoid sorrows. While that seems very good and pleasant, constant prosperity and good fortune do a person harm. He falls into a variety of passions and sins, and angers the Lord, while those who live a life of sorrow come closer to the Lord and more readily attain unto salvation, for the Lord called the life of happiness the broad path. The wide gates and the broad way lead to destruction, and many there be who take that way (Matthew 7:13). It is the narrow way and the strait gate which lead to life eternal, and few there be who find it (Matthew 7:14). Thus, according to His love for us, seeing the possible benefit [of sorrows] to those who are worthy, the Lord moves many off the broad road and puts them on the narrow, sorrowful path, so that in [their] patient endurance of sickness and sorrow, He might effect their salvation and grant them life eternal.
The enemy constantly endeavors to awaken in the abyss of the human heart a great turmoil about trifles. This is one of his tricks to blind our soul to the sun of truth, Christ our Lord, hidden in the heart's core of every one of our neighbors.
Put aside bodily considerations when you stand in prayer, lest the bite of a flea, a gnat or a fly deprive you of the greatest gain afforded by prayer.
Pray that you may be granted the grace to read the Fathers with the right understanding, the grace to live up to the standards they put before you, and the grace clearly to see your own frailty. You will not long be left wanting and waiting. God will give you help.
Do not be always wanting everything to turn out as you think it should, but rather as God pleases; then you will be undisturbed and thankful in your prayer.
When you receive from Heaven the gift of patience, be attentive and vigilant over yourself, so as to hold and keep within yourself the grace of God, lest sin should creep unnoticed into your soul or body and drive away this grace.
How harmful is the praise of man! Even though a person may have done something worthy of praise, when he enjoys the sound of praise he is already deprived of future glory, according to teachings of the holy fathers.
A life lived in the world can be as good, in the eyes of God, as one spent in a monastery. It is indeed only the keeping of God's commandments, love of all, and a true sense of humility that matter, wherever we are.
I think it best that a man should have a little bit of all the virtues. Therefore, get up early every day and acquire the beginning of every virtue and every commandment of God. Use great patience, with fear and long-suffering, in the love of God, with all the fervor of your soul and body. Exercise great humility, bear with interior distress; be vigilant and pray often with reverence and groaning, with purity of speech and control of your eyes. When you are despised do not get angry; be at peace, and do not render evil for evil. Do not pay attention to the faults of others, and do not try to compare yourself with others, knowing you are less than every created thing. Renounce everything material and that which is of the flesh. Live by the cross, in warfare, in poverty of spirit, in voluntary spiritual asceticism, in fasting, penitence and tears, in discernment, in purity of soul, taking hold of that which is good. Do your work in peace. Persevere in keeping vigil, in hunger and thirst, in cold and nakedness, and in sufferings. Shut yourself in a tomb as though you were already dead, so that at all times you will think death is near.
You describe how bitterly you regret the inefficacy of your prayers. Beware: to wish for consolation or revelation in prayer is a sure sign of pride. Pray humbly, in perfect simplicity, seeking salvation only through forgiveness, & having faith that God will extend to you His mercy - as He did to the publican.