First of all, only people who have converted to the Catholic Faith can receive forgiveness of their sins, so if you have not done this yet, you should do so as soon as possible. You need to renounce all heresies, heretics and antipopes, learn the true Catholic Faith, and convert to it, or you cannot obtain salvation.
For Catholics, in these last days it is essential to examine one’s conscience daily, and to do it VERY WELL, and be firmly resolved to avoid all sin, insofar as we are able, and all occasions of sin. Since there are very few, if any, Catholic priests left in the world, that is to say few who have not lost the faith by holding to heresy, we may perform this exercise and confess our sins to a priest in the Communion of Saints daily (such as St. Dominic), doing penance, and praying for forgiveness and grace.
Without a priest available, it is also a good idea, if you are comfortable doing so, once your sins are thus confessed, to disclose them to a highly trusted Catholic friend, for the sake of humiliation, and you may even ask him to suggest penance for you. It has been related by saints that penance done out of obedience is more pleasing to God than penance done independently of our own free will (which also is pleasing to God), and a friend may be more inclined to suggest a penance that we do not like at all (which is very pleasing to God, if we do it from sincere contrition).
Pope Julius III, Council of Trent, Session 14, Chapter 4, ex cathedra: "Contrition, which holds the first place amongst the aforesaid acts of the penitent, is a sorrow of mind, and a detestation for sin committed, with the purpose of not sinning for the future. This movement of contrition was at all times necessary for obtaining the pardon of sins; and, in one who has fallen after baptism, it then at length prepares for the remissions of sins, when it is united with confidence in the divine mercy, and with the desire of performing the other things which are required for rightly receiving this sacrament.
"Wherefore the holy Synod declares, that this contrition contains not only a cessation from sin, and the purpose and the beginning of a new life, but also a hatred of the old, agreeably to that saying; Cast away from you all your iniquities, wherein you have transgressed, and make to yourselves a new heart and a new spirit. And assuredly he who has considered those cries of the saints; To thee only have I sinned, and have done evil before thee, I have laboured in my groaning, every night I will wash my bed, I will recount to thee all my years, in the bitterness of my soul, and others of this kind, will easily understand that they flowed from a certain vehement hatred of their past life, and from an exceeding detestation of sins.
"The Synod teaches moreover, that, although it sometimes happen that this contrition is perfect through charity, and reconciles man with God before this sacrament be actually received, the said reconciliation, nevertheless, is not to be ascribed to that contrition, independently of the desire of the sacrament which is included therein."
(always beg the Blessed Virgin, through the Holy Rosary, to obtain for you from God the grace of PERFECT CONTRITION, which is none other than Divine charity, the love of God)
"And as to that imperfect contrition, which is called attrition, because that it is commonly conceived either from the consideration of the turpitude of sin, or from the fear of hell and of punishment, It declares that if, with the hope of pardon, it exclude the wish to sin, it not only does not make a man a hypocrite, and a greater sinner, but that it is even a gift of God, and an impulse of the Holy Ghost, --who does not indeed as yet dwell in the penitent, but only moves him, --whereby the penitent being assisted prepares a way for himself unto justice.
"And although this (attrition) cannot of itself, without the sacrament of penance, conduct the sinner to justification, yet does it dispose him to obtain the grace of God in the sacrament of Penance. For, smitten profitably with this fear, the Ninivites, at the preaching of Jonas, did fearful penance and obtained mercy from the Lord. Wherefore falsely do some calumniate Catholic writers, as if they had maintained that the sacrament of Penance confers grace without any good motion on the part of those who receive it: a thing which the Church of God never taught, or thought: and falsely also do they assert that contrition is extorted and forced, not free and voluntary."
The Revelations of St. Birgitta of Sweden, Book 4, Chapter 89:
‘The Son speaks: “Whoever desires to be a fighter has to be noble in spirit and get up again if he falls, trusting not in his own power but in my mercy. A person who does not trust in my goodness has the following thoughts: 'If I make any attempts at restraining the flesh by fasting or struggling in vigil, I will not be able either to persevere or to keep myself from vices, for God does not help me' - that person deserves to fall.
“Hence, a person who wants to be a spiritual fighter trusts in me and is confident that he will be able to achieve it with the aid of my grace. So he should have the intention of doing good and avoiding evil and of getting up again whenever he falls. He should say this prayer:
'LORD God Almighty, Thou who guidest all souls toward the good, I am a sinner who has strayed far away from Thee through my own wrongdoing. I thank Thee for leading me back to the right path, and I ask Thee, gracious JESUS, who hung on the cross in blood and sorrow, to have mercy on me. I entreat Thee by Thy five wounds and by the pain that passed from Thy shattered veins to Thy heart. Deign to keep me safe today, lest I fall into sin. Give me the power to withstand the spears of the enemy and to get up again manfully, should I chance to fall into sin.'
In addition, in order that the fighter may be able to persevere in the good, let him pray in this way:
'O, LORD God, for whom nothing is impossible and who can do all things, give me the strength to carry out good works and to be able to persevere in the good.'
“After this, he should take his sword in hand, that is, he should make a good confession, which must be polished and gleaming. It must be polished by a careful examination of conscience regarding how and how much and where he has failed and why. It should also be gleaming in the sense that he must not be ashamed of anything nor hide anything nor describe a sin in a way other than he has committed it. This sword should have two sharp edges, namely, the intention of no longer sinning and the intention of making up for the sins he has committed. The point of the sword should be contrition. This slays the devil whenever a man who earlier delighted in sin feels contrition and sorrow for having provoked me, his God, to anger. The sword should have the hilt of the consideration of God's great mercy. His mercy is so great that no one is such a sinner that he cannot obtain forgiveness, provided he asks for it with a will to improve.
“The sword of confession, then, must be held with this idea that God has mercy on all. However, in order that his hand may not be cut by the edges, a piece of iron is placed in between the edge and the hilt. A pommel prevents the sword from falling from his hand. Similarly, a person who holds the sword of confession and hopes in God's mercy for the remittance and cleansing of sin must beware not to let it fall by presuming on God's forgiveness. To prevent this there is the bolt of godly fear that makes him afraid that God will take away his grace and display anger because of his presumption. In order that his operative hand may not be cut or impaired, a piece of iron is placed between the hand and the edge. This is the consideration of God's fairness, for, though my justice is so great that I leave nothing unexamined or unpunished, yet I am also so merciful and fair that I demand nothing beyond what nature can bear. Moreover, I forgive great punishment for the sake of a good intention and great sin in return for a little reparation.
“The knight's coat of mail represents abstinence. Just as a coat of mail consists of many small rings of chain, so too abstinence consists of many virtues, for example, abstinence from immoral sights or things affecting the other senses, from gluttony and lust and superfluity, and from many other things that St. Benedict laid down as forbidden. One cannot put this coat of mail on alone without another's help.
“Therefore, my Mother, the Virgin Mary, should be invoked and venerated, for every good example and type of virtue are to be found in her. If she is steadfastly invoked, she will indicate to your spirit all the perfect types of abstinence.
“The helmet stands for perfect hope. It has two openings, as it were, through which the knight can see. The first opening is the consideration of what things must be done, and the second that of what things must be avoided. Everyone who hopes in God should always consider what must be done or avoided in accordance with God's will. The shield stands for patience with the help of which one can cheerfully endure anything that happens.”
PRAYERS BEFORE EXAMINATION
Apostles’ Creed, Our Father, Hail Mary, Glory Be
Come, Holy Spirit, fill the hearts of Thy faithful, and enkindle in them the fire of divine love. Send forth Thy Spirit and we shall be created. And Thou shalt renew the face of the earth.
My God, I firmly believe that Thou art here present; that Thou knowest and seest all my sins, and that Thou alone canst give me light and grace to see and know in what way I have offended Thee. O dear JESUS, grant that I may examine my conscience well; that I may think of nothing which may distract me from the great duty which I am about to perform.
Mary, my dear Mother, pray for me. Amen.
PRAYERS BEFORE CONFESSION
I confess to almighty God, to blessed Mary ever Virgin, to blessed Michael the Archangel, to blessed John the Baptist, to the holy apostles Peter and Paul, and to all the saints that I have sinned exceedingly in thought, word, and deed, through my fault, through my fault, through my most grievous fault. Therefore, I beseech blessed Mary ever Virgin, blessed Michael the Archangel, blessed John the Baptist, the holy apostles Peter and Paul, and all the saints, to pray for me to the LORD our God. Amen.
O Mary, Mother of JESUS, help me to be truly sorry for having displeased thy divine Son so that I, a despicable and wicked, sinner, may be washed from every stain and cleansed from every sin.
O LORD God, Heavenly King, deign that in Thy great condescension, I may be heard in the presence of the Holy Confessors in Thy heavenly host (or a specific priest, such as St. Dominc), to whom I now direct my confession, that I may hold back nothing that impedes Thee from entering into my soul and working in me with Thy grace. Grant, O merciful Father, that by this way I may be granted absolution, perfect contrition, true horror of even the smallest sin, and I beseech Thee, O loving JESUS, to bestow upon me those great gifts of sanctifying grace and final perseverance. Amen.
(Bless me father, for I have sinned...)
PRAYERS AFTER CONFESSION
ACT OF CONTRITION
O my God! I am heartily sorry for having offended Thee, and I detest all my sins, because I dread the loss of heaven and the pains of hell, but most of all because they offend Thee, my God, who art all good and deserving of all my love. I firmly resolve, with the help of Thy grace, to confess my sins, to do penance, and to amend my life.
ACT OF HOPE
O my God! Relying on Thy infinite goodness and promises, I hope to obtain pardon of my sins, the help of Thy grace, and life everlasting, through the merits of JESUS Christ, my LORD and Redeemer.
PRAYERS OF THANKSGIVING TO GOD
I thank and bless Thee, dear Saviour, for having pardoned me my sins. I will never more offend Thee; but for the future try to love and please Thee more and more.
Bless the LORD, O my soul, and let all that is within me bless His holy name. Bless the LORD, O my soul, and forget not all that He hath done for thee. As a father hath compassion on his children, so hath the LORD compassion on them that fear Him.
O holy Virgin Mary, and all ye angels and saints, bless and praise my dear JESUS for His great goodness to me, His little sinful child.
JESUS, Son of David, have mercy on me! O God, be merciful to me a sinner! Sprinkle me with Thy blood, O JESUS, and I shall be made whiter than snow!
PRAYER BEFORE PENANCE
O just and merciful JESUS, I beg Thee to inspire me with Thy grace, to enlighten my mind and my will that I may be moved to fitting penance for my sins against Thy Majesty, who livest and reignest with the Father and the Holy Ghost, world without end. Amen.
O my God, I offer this penance to Thee, in union with all the prayers said by JESUS during His holy life and bitter Passion, to satisfy Thy infinite justice, which I have offended by my many sins and offer it for the souls in Purgatory, retaining only that which may avail me of the grace to live Thy holy Faith in truth and righteousness. Amen.