To a layman who asked about Noetic Prayer (Lord Jesus Christ, have mercy on me, a sinner.), Elder Ephraim of Katounakia had this to say:
Set aside half an hour out of the twenty-four to say the Prayer. Whenever you are able; but the evening is best. Say it without using the prayer rope - in supplication, pleading, and with tears. 'Lord Jesus Christ, have mercy on me.' Cultivate this, and you'll see what fruit it brings. From half an hour, it will become an hour. And guard this hour. Whether the phone is ringing, or you have this task you need to do now, or you're sleepy, or some blasphemy is confronting you. Nothing. Turn off the phone. Finish your tasks. Do this half hour and you'll see. You've planted a little tree, and tomorrow or the day after it will bear fruit. St. John Chrysostom and St. Basil both began like this and became luminaries for the whole world. St. Symeon the New Theologian had experiences of the Uncreated Light while still a layman. He was a layman. How many laymen appear as such exteriorly, but deep down are monastics!
From Obedience Is Life: Elder Ephraim of Katounakia, by Elder Joseph of Vatopaidi, p. 196.