We just began a new relationship with the Lord. Our sins are forgiven and we have a clean slate. But we also need to learn from our past and grow closer to God, and a great way to do this is to repent. Repenting is the process of learning from our mistakes, turning to God, and changing our ways so we don't make the same mistake again.
Every time we sin, we glorify the devil, and distance ourselves from God. But with each act of repentance, we break down these barriers, glorify His name and grow closer to the Lord by separating ourselves from sin.
God knows all, and there is nothing hidden that will not come out into the light (Luke 8:17). Therefore, we need to confess our sins to God and change our ways. This is a simple process, and does not require that we go to church and confess to a priest. Many times, this process just gets in the way and prevents us from repenting. All believers in Jesus are priests (1 Peter 2:5). Since Jesus is the Most High priest, you can confess directly to the Lord (Hebrews 4:14-15). And it's so easy we can start right now.
Humble yourself before the Lord & recognize your sins
Turn to the Lord & ask for forgiveness
Learn from your mistakes, change your ways, try to not make the same mistake again
Since we live in a world that surrounds us with sin, we should continue the above process throughout our lives, with the hope that one day we would sin no more. But in order not to sin, we need to understand what it is. Sin is not doing right in God's eyes (1 John 3:4). So everyone should know God's Word in order to please Him. Although we worship God through Jesus in the spirit, start by having a good understanding of the 10 Commandments
and continue building a relationship with God by reading scripture for yourself.