By being baptised and by practicing the positive and unchanging essentials for living a Christian life which are based on humility, prayer, observing God's law and Church regulations and going to mass.
Religion alone can't save anyone. Only trusting Christ to forgive you of your sin can save you. If you have a bible, look up Romans 3:10, Romans 6:23, and Romans 10:13. They show that 1) you are a sinner 2) that you need a savior and 3) that if you pray and for forgiveness, and put your faith in Christ to save you, that you can be saved. No religion can save you. Repentance leads to Salvation.