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.
Fire makes iron impossible to touch, and likewise frequent prayer renders the intellect more forceful in its warfare with the enemy. That is why the demons strive with all their strength to make us slothful in attentiveness to prayer, for they know that prayer is the intellect's invincible weapon against them.
And when you pray, see that you ask not for what is alien to your life, and provoke the Lord. Ask not for money, not for human glory, nor power, nor for any of the things that pass away. But seek for the kingdom of God, and all that is needed for your body will be provided; as the Lord Himself has said: Seek ye the kingdom of God, and his justice, and all these things will be added unto you (Matthew 6:33).
'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.
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.
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.