We become accustomed to reading our prayers from books - using the prayer passed down to us by Our Lord, and by the Holy Fathers who had achieved the art of prayer. But we must not stop at this. It is necessary to extend ourselves further. Once we have become accustomed to turn our ears and hearts to God using this help given by others, we should then also attempt to bring something of our won to Him, so to speak; to pass on into our own prayerful conversation with God; to raise ourselves toward Him; to open ourselves to Him; to confess to Him the contents and needs of our souls.
He says prayer "should be an unceasing offering of oneself to Him."
To achieve this, it is necessary to begin - as often as possible during the day - by calling out to God from the heart in short words, according to one's needs and in ways appropriate to the events around you.
Above taken from The Path of Prayer: Four Sermons on Prayer by Saint Theophan the Recluse pp. 13-15.