I do what Christ did. I teach when I can, and let them come to me if they're drawn by the Father. It's folly, in my opinion, to go into the lion's den and poke the lions. No one will listen to you. So just do your thing, go your way, and allow God to bring them to you. If you encounter resistance to the point of vain babblings (2 Tim. 2:16), kick the dust off and walk away.
If you pray for God to bless your ministry, whatever it may be, He will do so if you are willing to obey and serve Him in this area. If you're sincere and humble at heart, He will bless what you do. But the point of ministry isn't "numbers", it's the message. God's Word doesn't return to Him void. So spread the message and depend on the Holy Spirit to water the seeds you sow.
You don't need to see the fruit of your labor on this side of eternity.