Go somewhere that you can be alone. Get on your knees and start confessing to God the Father in Heaven that you realize you are not perfect and that you are a sinner. Think about the sins you are guilty of ( WE ALL ARE) and say you will stop them and ask for forgiveness in the name of Jesus Christ. You must be speaking truthfully from your heart like a little child speaking the truth. Confess with your mouth that you believe Jesus Christ came to the earth and was born into flesh to suffer for our sins as a sacrifice. That Christ was crucified and rose 3 days later and performed miracles in front of thousands of witnesses for 40 days. Then Jesus rose up into the clouds (the same way He will return) and is seated at the right hand of the Father. Romans 10:9 "because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved."
Mat 6:22 The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.
Mat 6:23 But if thine eye be evil, thy whole body shall be full of darkness. If therefore the light that is in thee be darkness, how great is that darkness! Mat 6:24 No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.