The Apostles would never have left Jerusalem if they would have taken your advice
The holy Apostles were confirmed by Our Lord Jesus Christ and were filled with the Presence of God the Holy Ghost. They were commanded to instruct the nations in the true Faith. Your Catholic Faith, as well as anyone else's, is a product of the faithfulness of the Apostles and THEIR SUCCESSORS to do that which Our Lord commanded.
Show me a place in the Holy Scriptures, even one, where an individual who was not an Apostle (i.e. a Bishop), a deacon or a priest was commanded to go out and teach OR where they actually did so fruitfully. Apollos was a layman, and he needed to be instructed in the way of God "more perfectly" because his "witnessing" was obviously not effective.
The Apostles left Jerusalem under Divine unction. They did not get together and decide upon some clever method of "choosing a passage of Scripture", which they would not have been able to do anyway, since they had but the Old Testament and it was contained in scrolls as large as a small child's body. Not very easy to just grab and sit and read.
If you want to do things the way the Apostles did them, why not start by being so full of the influence of God the Holy Ghost that your life and actions gather a crowd of convinced unbelievers. Then, when they are all assembled around you, begin to preach, NOT to dialogue, and make unqualified, strident claims about how your listeners are not only lost in their sin, but are personally responsible for the suffering and death of the Son of God, the second Person of the Most Holy Trinity.
Let's review:
1. Have a specific command from Our Lord to preach and confirm disciples
2. Be fully convinced that you intend to bring your listeners, if any, into the One True Church and not just into some protestant "persona relationship" with the protestant false jesus
3. Preach a message of condemnation of sin and the judgment of all those who are thus guilty before God of not only their sin but of their continual rejection of the Divine Redeemer
Yes, it sounds like you're an Apostle, all right...
...or you're just trying to circuмvent God's established Order, namely, the hierarchy of Holy Church, because you're frustrated at how the protestant heretics seem to make more 'converts' than Catholics do.
Please, oppositeman and others, bear in mind that protestant rhetorical tactics won't work to make converts to the True Faith. Your job is to point TO the answers, which Holy Church teaches, not to become a Lone Ranger unauthorized 'teacher' yourself.
Immaculate Heart of Mary, triumph soon!
Most Sacred Heart of Jesus, have mercy on us.