My brother sinner, this is the preparation you must undergo before you repent and go to confession. Know firstly that repentance is a returning from the devil to God, which comes about through pain and ascesis. -- St. John of Damascus
Repentance and confession of sin is a fundamental tenet of Gospel. The message of the Forerunner, of Christ Himself, and of the Apostles make it clear that, from the beginning, the call to repentance is directed to those who already believe.
The therapeutic method of the Church has the intention of transforming a sinner into a Saint. Holy Confession is part of the cure.
Either of these booklets will help you prepare for confession. Both are very good and offer a list of questions to help you examine your conscience. The first is based on the Sermon on the Mount; the second on the 10 Commandments.
The world glorifies a lifestyle of sin as glamorous and ridicules humility as a weakness. Life in the Church is the exact opposite. Humility is the queen of the virtues, for it opens the gates of Paradise. The Lord established repentance as the way of salvation.