Saint Innokenty Bishop of Alaska answers this important question in his writing The Way into the Kingdom of Heaven:
Therefore, when a Christian, humbly and obediently, has accepted Christ’s faith in all its purity, without any corrections or misinterpretations, then the following are the requirements to receive the gifts of the Holy Spirit:
Purity of heart and chastity
Listening to the voice of God
Reading the Holy Scriptures
Sacraments of the Church, especially Holy Communion
To receive gifts from the Holy Spirit, you must, first of all, cleanse your heart of sin, self-love, and pride. The Holy Spirit always surrounds us and wishes to fill us, but the evil nesting within us, like a wall, impedes His path. Any sin keeps the Holy Spirit away from us, but carnal impurity and pride are especially offensive to Him. So, if we do not want the Holy Spirit, Whom we received in Baptism, to depart from us, or if we have pushed Him away through our sinful life and now want Him to return, here is what we must do:
1. Cleanse yourself with repentance and sincere confession. Then shun all sinful thoughts and wishes. In view of the terrible lewdness of contemporary society, a Christian must protect himself from all that may pollute his soul and keep his flesh from lustfulness. Indeed, our body was designed to be the temple of the Holy Spirit. When a person is clean internally and externally, the Holy Spirit settles within him. In the presence of chastity, the only obstacle for the Holy Spirit is your pride in your righteousness and your regard of His gifts as your just reward. If you have unfortunately defiled yourself, then stop sinning and repent. With a contrite heart regret that you have offended God, your most loving Father, and strive to live with greater vigilance. Then even you will be able to receive the Holy Spirit.
2. One of the surest ways of attracting the Holy Spirit is by humility. Even if you are an honest, just, good, and merciful man, in a word, even though you may have achieved much goodness, keep considering yourself as an unworthy servant of God. Indeed, if we examine our good works more closely, we will see that none of them are completely beyond reproach. For example, if we give alms or help someone, how often do we add conceited, regretful, self-interested, judgmental, or other such unkind thoughts to our alms or help. Of course, every good deed always remains good, even when it is imperfect. It can be likened to gold which has value even before it is purified. But as gold becomes more precious when an experienced craftsman purifies and works it, so let us entrust our good deeds to the Heavenly Master that He will make them even more valuable.
Thus, if you wish your good deeds to please God, do not boast about them. You are not the master but only an apprentice. As craftsmanship gives value to gold, so a pure and unselfish Christian love, which stems from the Holy Spirit, gives value to our good deeds. Everything that is done without Christian love, i.e., without the Holy Spirit, is not yet a fully valued good deed. Without the Holy Spirit a person remains poor and pitiful.
But humility consists not only of realizing your unworthiness but also of bearing the various sorrows and adversities of life with patience and without grumbling, considering them as sent or allowed by God for our benefit. Do not say, "How unfortunate I am!" But say, "I deserve a still greater punishment for my sins!" And ask God not so much to deliver you from adversities as to give you patience and courage to bear them.
3. The Holy Spirit can also be received by listening attentively to the voice of God. God speaks to us by means of the internal voice of our conscience and through external circumstances. It is very important to develop sensitivity in order to hear more clearly what God suggests to us. He, as a most loving Father, cares for you. Daily He calls you to Himself, warns you and enlightens you. For instance, are you unhappy, has someone offended you, has misfortune befallen you, or are you ill? In these you can hear the voice of God, calling you to repent and improve. In time of sorrow, instead of seeking help from others or consoling yourself by frivolous distractions and amusements, turn to God and seek guidance and help from Him alone.
Or suppose that you are prospering and living well and that everything flows smoothly. Consider this also to be the voice of God. Here God teaches you to be as merciful to those in need as He is merciful to you. It is dangerous and sinful to ignore the voice of God, to remain unrepentant and unimproved during times of hardship, to fail to thank God, or not to help others when you have plenty. Even more ruinous is to do the opposite of that to which God is leading us: to grumble and become embittered in difficult circumstances or to forget God and live only for pleasure in fortunate surroundings. What might then result is that God, after repeated teachings, will turn away from you as from a stubborn child and will abandon you to your own desires. Then passions will easily overcome you, your intellect and conscience will become dulled, and you might reach a point at which you will justify even your vilest crimes as natural and common human weakness. In order to avoid such a fall, it is necessary to become sensitive to the voice of God in the Holy Spirit and to follow His admonitions.
4. The Holy Spirit can be received through prayer. Prayer is the simplest, surest, and most available means to receive the Holy Spirit. Because we are composed of body and soul, they both should participate in prayer. The primary elements of prayer are concentration and sincerity, which are attained by inner effort. Nevertheless, the body should not remain uninvolved; it can and must assist the soul in prayer by standing in reverence, making prostrations, making the sign of the cross, raising the hands, and reading the prayers aloud. Other favorable external conditions also help in prayer: solitude, silence, ikons with burning lampadas before them, incense, and when in church, church art and architecture along with soft and harmonious singing, beautiful ceremonies, etc.
But to achieve concentration and warmth during prayer is not easy. Here, first of all, it is important to establish a regular time for prayer (for instance, mornings and evenings), and to develop stability and patience. You should constantly overcome haste, distraction, indifference and insincerity. In addition, you must strive to warm your heart with love for God. Only a sincere prayer brings comfort and peace to the heart. Much effort is necessary in order to learn to pray properly, and, as we well know, all the righteous ones strove throughout their lives to learn the art of prayer. Nevertheless, your personal effort is not enough. It is the Holy Spirit who makes our prayer to be fervent and to come from the bottom of our heart. This was well known to the saints who, inspired by the Holy Spirit, stood day and night in prayer in sweet rapture, failing the while to notice the time fleeting away.
Pray even though at first your prayer may be weak and imperfect because of your sinfulness and estrangement from God. Pray with diligence and fervor; train yourself to be sincere in your conversation with God. Thus, little by little you will learn to pray and will start to feel a sweet comfort. The Holy Spirit will have mercy on you and will come and reside in you if you show faithfulness in your efforts at prayer.
The Holy Scripture teaches: Pray without ceasing (1 Thess. 5:17). How is this possible for people living in a secular world? If you are to pray all the time, how then are you to perform your other duties? The advice of perpetual prayer is directed not toward outward but toward inner prayer. If desired, you can turn to God internally whether you are alone or with others. Only he who does not want to pray will not find time for prayer.
5. Fasting and works of mercy aid prayer. The Fathers of the Church recommend: If you want your prayer to fly up to God, then give it two wings, fasting and almsgiving.
What is fasting and why is it necessary? Fasting is a voluntary self-restriction in food, drink, and pleasure. The purpose of fasting is to quiet or calm and lighten the body and to make it obedient to the soul. Overfilled flesh demands comfort and rest, disposing us to laziness, which hinders prayer and meditation. In the manner of an unbridled servant, the well-fed body rises up against its master, the soul, and wants to rule over it. While fasting, you should limit not only the type of food (dairy and meat products) but also its amount, restricting yourself to the minimal needs of the body. Then your fasting will become useful.
While fasting outwardly you should also fast internally, restraining your tongue from sinful, idle chatter and moderating your desires and your anger while driving off unkind thoughts and impure fantasies. Experience shows that there is nothing harder than to stop the wandering of thoughts and to direct your mind to thoughts of God and prayer. This may be likened to the taming of wild horses who have long been stubborn and unruly.
Non-spiritual people do not even suspect how difficult it is to control the wandering of thoughts. Being occupied with worldly affairs, they consider their thoughts to be busy with worthwhile concerns. Only when they begin to strive toward a spiritual life and try to reflect on spiritual topics, do they begin to notice that their thoughts are murky. This is somewhat like the waters of a shallow lake. As long as its surface remains undisturbed, it looks clear; but when it is stirred, the silt from its bottom darkens the water, making it appear murky. Likewise, in the depths of our heart there lay various passions. Like silt, they rise and darken the soul when a Christian attempts to expose and struggle with them. As the Holy Fathers have explained, when people turn to God, the devil strives to darken their soul with bad thoughts and feelings in order to confuse them and distract them from their good intentions. But do not yield to his snares, and do not stray from the path of salvation. Remember that no one can simultaneously think about two subjects. If you occupy your mind with good thoughts (reading spiritual books or studying some worthwhile subject), the bad ones will not be able to linger in your mind.
Love reveals itself in works of mercy. Among such works are to feed the hungry, to give drink to the thirsty, to clothe the naked, to visit and help the sick and the imprisoned, to give refuge to the homeless, and to be concerned about orphans. All this should be done with sincere and unselfish love, without any boasting or expectations of gratitude. The Savior teaches regarding this: Do not let your left hand know what your right hand is doing, that your charitable deed may be in secret; and your Father who sees in secret will Himself reward you openly (Matt. 6:3-4).
6. The Holy Spirit may be received by piously reading and listening to the Holy Scriptures. Being the Word of God, they hold a great treasury of spiritual enlightenment and wisdom. The Holy Scriptures are one of God’s greatest blessings, which can be used by anyone wishing to do so. In them, the divine wisdom is presented in such an easy, approachable manner that even the simplest and most uneducated person can understand it. Many cases are recorded throughout Church history and in the lives of the saints, in which the simplest of people, while studying Holy Scripture, were enlightened, became pious, and received abundant gifts of the Holy Spirit even while some scholars and intelligentsia read the Holy Scripture and became confused and fell into heresy. The difference was that while the first read it with simplicity of heart, seeking in it spiritual direction, the second approached it with criticism, attempting to uncover inconsistencies. Considering themselves wise and all-knowing, these last succumbed to pride and even became false teachers. Be aware that our small and imperfect intellect cannot encompass God’s wisdom. God enlightens those who with a pure and kind heart turn to Him in search of enlightenment. Therefore, in reading the Holy Scriptures, lay aside all worldly wisdom and inquisitiveness. Submit to the word and the will of Him who speaks to you through Holy Scripture, and beseech Jesus Christ to enlighten you and show you the path to salvation.
There are many other books besides Holy Scripture that are beneficial for reading: the works of the Holy Fathers, the lives of the saints, inspirational stories, sermons, and other praiseworthy writings of Orthodox authors. From the books available to you, read those that are based on Holy Scripture and are in accord with the teaching of the Orthodox Church. Beware of those poisoned by heresies and non-Christian ideas.
7. Communion is another source for receiving the Holy Spirit. Regarding it, Jesus Christ said: He who eats My flesh and drinks My blood, abides in Me, and I in him. (He) has eternal life, and I will raise him up at the last day (Jn. 6:54-56). When Christians partake of Holy Communion they unite inexplicably with Jesus Christ and start partaking of His divine life. Therefore, you must go to Communion with faith, having cleansed your soul by repentance, with a realization of your unworthiness, and with the hope of God’s mercy. Since God is one and indivisible, when Christians accept Jesus Christ into their heart, they accept the Holy Spirit and the Heavenly Father at the same time and thus become a living temple of God.
As witnessed in the Acts of the Apostles and other ancient Christian writings, the faithful of the first centuries took Communion every Sunday, which then was called the Lord’s day. Undoubtedly, because of this constant communion with Jesus Christ, they were as "of one heart and one soul" (Acts 4:32). My God, what a difference there is between them and us. How many among us seldom partake of Holy Communion, sometimes avoiding it for years!
Those who neglect to take Holy Communion do not love Jesus Christ and will not receive the Holy Spirit, and consequently will not enter the Kingdom of Heaven. So, for the sake of your salvation, partake of Communion as often as possible. The Body and Blood of Christ is a true cure for many spiritual and bodily infirmities. And who among us is perfectly healthy? Who would not want to receive helpful relief? The Body and Blood of our Lord Jesus Christ is the nourishment which sustains us on the path to the Kingdom of Heaven. Is it possible to complete a long and difficult journey without sustenance? The Body and Blood of Jesus Christ is the holiness bestowed on us by Jesus Christ Himself for our sanctification. Who would refuse to be a partaker of such holiness? Therefore, do not be lazy in stepping up to the Chalice of Life, but approach it with faith and fear of God.
In summary, these are the means of receiving the Holy Spirit: purity of heart, chastity, humility, listening to the voice of God, prayer accompanied by fasting and charity, reading Holy Scripture, meditation, and partaking of Holy Communion. Of course, each of these individually is effective for receiving the Holy Spirit, but it is best to resort to all of them for our salvation.
To this it is necessary to add that if we somehow fall into sin and thereby distance ourselves from the Holy Spirit, we should not despair and think that we have irrevocably lost all blessings, but let us quickly prostrate ourselves before God with deep repentance and prayer, and the All-merciful Holy Spirit will again return to us.