I believe Bunyan’s prayer from Pilgrim’s Progress is the very best.
“God be merciful to me a sinner, and make me to know and believe in Jesus Christ. For I see that if His righteousness had not been offered, or if I have no faith in that righteousness, I am utterly cast away. Lord, I have heard that You are a merciful God and have ordained that Your Son Jesus Christ should be the Savior of the world. Moreover, You are willing to give Him for a poor sinner like me (and I am a sinner indeed). Lord, take therefore this opportunity, and magnify Your grace in the salvation of my soul, through Your Son Jesus Christ, Amen.”