If you would like to to start a relationship with God and believe that Jesus died for you here is a prayer that might help:
Jesus, thank you that you died to take the blame for the things I've done wrong. Please forgive me and free me from sin. Come into my life and help me to understand and do things your way. Thank you Jesus, Amen.
If you aren't there yet but are wondering whether God exists how about this one:
God are you there, please show me because I want to know.