Do not pray for the fulfillment of your wishes, for they may not accord with the will of God. But pray as you have been taught, saying: 'Thy will be done in me' (Luke 22.42). Always entreat Him in this way, that His will be done. For He desires what is good and profitable for you, whereas you do not always ask for this. Often when I have prayed, I have asked for what I thought was good, and persisted in my petition, stupidly importuning the will of God, and not leaving it to Him to arrange things as He knows is best for me, But when I have obtained what I asked for, I have been very sorry that I did not ask for the will of God to be done, because the thing turned out not to be as I thought.
Do you wish God to hear your prayer immediately, brother? When you lift your hands up to heaven, pray first of all, with your heart, for your enemies and God will grant you speedily whatever else you request.
He who prays with the lips, but neglects his soul and does not guard his heart, prays to the air and not to God; and he labors in vain, because God attends to the mind and fervor, and not to prolixity. One should pray with all one’s fervor, with one’s soul and mind & heart, with the fear of God, and with all one’s strength.
Our prayer reflects our attitude towards God. He who is careless of salvation has a different attitude toward God from him who has abandoned sin and is zealous for virtue but has not yet entered within himself and works for the Lord only outwardly. Finally, he who has entered within and carries the Lord within himself, standing before Him, has yet another attitude. The first man is negligent in prayer, just as he is negligent in life, and he prays in church and at home merely according to the established custom, without attention or feeling. The second man reads many prayers and goes often to church, trying at the same time to keep his attention from wandering and to experience feelings in accordance with the prayers which are read, although he is seldom successful. The third man, wholly concentrated within, stands with his mind before God, and prays to Him in his heart without distraction, without long verbal prayers, even when standing for a long time at prayer in his home or in church.... Every prayer must come from the heart and any other prayer is no prayer at all. Prayer-book prayers, your own prayers and very short prayers, all must issue forth from the heart to God, seen before you.
The one who prays ought never to halt his movement of sublime ascent toward God. For just as we should understand the ascent 'from strength to strength' as the progress in the practice of the virtues, 'from glory to glory' (2 Cor. 3:18) as the advance in the spiritual knowledge of contemplation, and the transfer from the letter of sacred writing to its spirit, so in the same way the one who is settled in the place of prayer should lift his mind from human matters and the attention of the soul to more divine realities.
Prayers at home are an introduction, a preparation for prayers in Church. Thus he who is not accustomed to pray at home can seldom pray diligently in Church. Experience bears witness to this: anyone can observe it for himself.
When you are praying, don’t rack your brains to find words. On many occasions the simple, monotonous stammering of children has satisfied their Father who is in heaven. Don’t bother to be loquacious lest the mind is bewildered in the search for words. The tax-collector gained the Lord’s forgiveness with a single sentence, and a single word charged with faith was the salvation of the robber. Loquacity in prayer often fills the head with foolish fancies and provokes distractions. Brevity on the other hand - sometimes only one word is enough - in general favors recollection.
'If our prayer is not in harmony with our deeds, we labor in vain,' Abba Moses often told the young monks. 'How are we to accomplish such harmony?' they asked him one day. 'When we make that which we seek fitting to our prayer,' explained the saint. 'Only then can the soul be reconciled with its Creator and its prayer be acceptable, when it sets aside all of its own evil intentions.'
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.