You ask about a prayer rule. Yes, it is good to have a prayer rule on account of our weakness so that on the one hand we do not give in to laziness, and on the other hand we restrain our enthusiasm to its proper measure. The greatest practitioners of prayer kept a prayer rule. They would always begin with established prayers, and if during the course of these a prayer started on its own, they would put aside the others and pray that prayer. If this is what the great practitioners of prayer did, all the more reason for us to do so. Without established prayers, we would not know how to pray at all. Without them, we would be left entirely without prayer.
However, one does not have to do many prayers. It is better to perform a small number of prayers properly than to hurry through a large number of prayers, because it is difficult to maintain the heat of prayerful zeal when they are performed to excess.
I would consider the morning and evening prayers as set out in the prayer books to be entirely sufficient for you. Just try each time to carry them out with full attention and corresponding feelings. To be more successful at this, spend a little of your free time at reading over all the prayers separately. Think them over and feel them, so that when you recite them at your prayer rule, you will know the holy thoughts and feelings that are contained in them. Prayer does not mean that we just recite prayers, but that we assimilate their content within ourselves, and pronounce them as if they came from our minds and hearts.
After you have considered and felt the prayers, work at memorizing them. Then you will not have to fumble about for your prayer book and light when it is time to pray; neither will you be distracted by anything you see while you are performing your prayers, but can more easily maintain thoughtful petition toward God. You will see for yourself what a great help this is. The fact that you will have your prayer book with you at all times and in all places is of great significance.
Being thus prepared, when you stand at prayer be careful to keep your mind from drifting and your feeling from coldness and indifference, exerting yourself in every way to keep your attention and to spark warmth of feeling. After you have recited each prayer, make prostrations, as many as you like, accompanied by a prayer for any necessity that you feel, or by the usual short prayer. This will lengthen your prayer time a little, but its power will be increased. You should pray a little longer on your own especially at the end of your prayers, asking forgiveness for unintentional straying of the mind, and placing yourself in God's hands for the entire day.
You must also maintain prayerful attention toward God throughout the day. For this, as we have already mentioned more than once, there is remembrance of God; and for remembrance of God, there are short prayers. It is good, very good, to memorize several psalms and recite them while you are working or between tasks, doing this instead of short prayers sometimes, with concentration. This is one of the most ancient Christian customs, mentioned by and included in the rules of St. Pachomius and St. Anthony.
After spending the day in this manner, you must pray more diligently and with more concentration in the evening. Increase your prostrations and petitions to God, and after you have placed yourself in Divine hands once again, go to bed with a short prayer on your lips and fall asleep with it or recite some psalm.
Which psalms should you memorize? Memorize the ones that strike your heart as you are reading them. Each person will find different psalms to be more effective for himself. Begin with Have mercy on me, O God (Psalm 50); then Bless the Lord, O my soul (Psalm 102); and Praise the Lord, O my Soul (Psalm 145). These latter two are the antiphon hymns in the Liturgy. There are also the psalms in the Canon for Divine Communion: The Lord is my shepherd (Psalm 22); The earth is the Lord's, and the fulness thereof (Psalm 23); I believed, wherefore I spake (Psalm 115); and the first psalm of the evening vigil, O God, be attentive unto helping me (Psalm 69). There are the psalms of the hours, and the like. Read the Psalter and select.
After you have memorized all of these, you will always be fully armed with prayer. When some disturbing thought occurs, rush to fall down before the Lord with either a short prayer or one of the psalms, especially O God, be attentive unto helping me, and the disturbing cloud will immediately disperse.
There you are; everything on the subject of a prayer rule. I will, however, mention once again that you should remember that all these are aids, and the most important thing is standing before God with the mind in the heart with devotion and heartfelt prostration to Him.
I thought of something else to tell you! You may limit the entire prayer rule just to prostrations with short prayers and prayer in your own words. Stand and make prostrations, saying Lord have mercy, or some other prayer, expressing your need or giving praise and thanks to God. You should establish either a number of prayers, or a time-limit for prayer, or do both, so that you do not become lazy.
This is necessary, because there is a certain incomprehensible peculiarity about us. When, for example, we go about some outward activity, hours pass as if they were a minute. When we stand at prayer, however, hardly have a few minutes gone by, and it seems that we have been praying for an extremely long time. This thought does not cause harm when we perform prayer according to an established rule; but when somebody prays and is just making prostrations with short prayers, it presents a great temptation. This can put a halt to prayer that has barely begun, leaving the false assurance that it has been done properly. Thus, the good practitioners of prayer came up with prayer ropes so that they would not be subject to this self-deception. Prayer ropes are suggested for use by those who desire to pray using their own prayers, not prayers from a prayer book. They are used as follows: Say Lord Jesus Christ, have mercy on me a sinner, and move one bead between your fingers. Repeat the prayer again and move another bead, and so on. Make a prostration during each repetition of the prayer, either a partial one from the waist or a full one to the ground, as you prefer; or, for small beads, make a prostration from the waist, and for large ones, a full one to the ground. The rule in all of this consists in having a definite number of prayer repetitions with prostrations to which are added other prayers in your own words. When deciding on the number of prostrations and prayers, establish a time limit, so that you do not deceive yourself as to haste when you perform them. If haste creeps in, you can fill up the time by making more prostrations.
How many prostrations should be done for each prayer is set down at the end of the Psalter with sequences in two categories, one for diligent people and the other for lazy or busy people. The elders now living among us in sketes or special kellia in places such as Valaam or Solovki serve the entire service according to this. If you would like to, now or some other time, you can perform your own prayer rule in this manner. Before you do this, however, get used to performing it in the manner prescribed for you. Perhaps you will not need a new rule. In any case, I am sending you a prayer rope. Try it! Note how much time you spend at morning and evening prayer, then sit down and say your short prayers with the prayer rope, and see how many times you go around the rope during the time usually required for your prayer. Let this quantity be the measure of your rule. Do this not during your usual prayer time, but at some other time, although do it with the same sort of attentiveness. The prayer rule, then, is carried out in this way, standing and making bows.
After reading this, do not think I am driving you into a monastery. I first heard about praying with a prayer rope from a lay person, not a monk. Many lay people and monastics pray in this way. It should be suitable for you, too. When you are praying with prayers that you have memorized and they do not move you, you may pray that day using the prayer rope, and do the memorized prayers another day. Thus, things will go better.
I will repeat once again that the essence of prayer is the lifting of the mind and heart to God; these little rules are an aid. We cannot get by without them because of our weakness. May the Lord bless you!
From The Spiritual Life and How to Be Attuned to It (Platina, CA: St. Herman of Alaska Brotherhood, 1996), Ch. 47, pp. 204-209. This is the best book on the spiritual life I have ever read. If I could only have two books, it would be this one and the Bible. I hope you will read it.