The Christian life is not completed in conversion. In the new birth, a person is changed from a sinner to a saint. Now, free to never sin again, the new Christian must go on to seek the Pentecost baptism of the Holy Spirit. Jesus also described this as the indwelling of the Holy Spirit: he is with you (in conversion), and shall be in you (in Pentecost).
Without this baptism, you will never be greatly successful in soul-winning. Indeed, Jesus Christ himself would have converted no one without the baptism of the Holy Spirit. You may witness, share your testimony, preach on the streets, or even be a pastor. But, your results will be meager. Few will come to Jesus, many will backslide, and the culture will remain unchanged.
Jesus gave the Great Commission to every believer. But, he never intended us to attempt the Great Commission without the promised power from on high. Will you persistently seek God for this baptism until you receive it?