Telling good news to everyone we met

Acts 16:11-21
Paul went outside the city gate to the river, they sat down and began to speak to the women who had gathered there. One of those listening was a woman named Lydia, the Lord opened her heart to respond to Paul's message. After they baptized, she invited Paul's team to her home.
They met a slave girl who had a spirit by which she predicted the future. This girl followed Paul and the rest of us, shouting, "These men are servants of the Most High God who are telling you the way to be saved."
Paul became so troubled that he turned around and said to the spirit, "In the name of Jesus Christ I command you to come out of her!
When the owner of the slave girl realized that their hope of making money was gone, they seized Paul and Silas and dragged them into the marketplace to face the authorities.They said, "These men are Jews, and are throwing our city into an uproar by advocating customs unlawful for us Romans to accept or practice."
In each place he visited, Paul normally went first to the synagogue (for which a minimum of ten men was required). At Philippi there was simply a group of women, meeting for prayer. So the church at Philippi, whose loving faithful support and unfailing concern would bring Paul such joy beings with the response of Lydia, a local businesswoman.
When Paul frees a slave-girl whose psychic powers earn her owners easy money, trouble quickly follows.
Why?
Drive devil spirit out with the name of Jesus Christ for his name is power.
Working with the Holy Spirit then the spirit will know.
The main reason is the man lost the hope of easy money, but he claimed false reason and try to recover his loss with lie and angry.
Who will be saved we do not know before we preach the gospel. God will open their heart if they are deserved. Our joy is show to them and talk to them the good news.
There was not synagogue in Philippi city.
How?
How to show my life of Christ and preaching the gospel to others?
The power of Christ and the grace of gospel may come upon one who I can't predicted.