David said, “I will confess my transgressions to the LORD”
A repentant heart recognizes that God is holy, nothing we do is good. There must be a place where we recognize the awesomeness of God and the nothingness of "me". You must come to the place where nothing else matters except striving to please God.
Sometimes when we first come to the Lord we are torn up like an old rag, and we realize such, we are guilty, we are ashamed, not of anything in particular, but we know we are worthless in comparison to anything of God. "Forgive me Lord, I am a sinner." And He forgives us, and hopefully we go on to complete His instructions for entering heaven at some point. Sometimes people become a bit self rightious and sin, repent casually and go on. They do not stay tender to Gods conviction, and that is when things will crumble in the relationship to Christ.
Everyday we may sin, that is why we must have a strong prayer life. The Lords prayer is a good outline for praying, not just reciting the verses, but putting them into action inserting our own words and circumstances. It is an OUTLINE, not a chant.
You must know the things that you do that are not pleasing to God, usually it's the things you hesitate on, and do it anyway. He already knows your sin, everyone of them, He wants you to confess this to Him personally. There are things we say and do everyday that can become sin, and we don't even think about it..after you have confessed and asked Him to forgive you for the sin you know you have, ask Him to reveal any secret sins, forgotten sins. Ask Him to convict you of sins you have forgotten so that you may further die to flesh. The last part of the Lords prayer about "And do not lead us into temptation, But deliver us from the evil on" very important that we ask God to hide us from Satan and his sneaky ways.
Most crooks in court are sorry for their actions...but they were not sorry enough to avoid doing them, they had a choice to do good, and chose evil. They are sorry because they got caught. We are all caught...and we should be sorry.