See page 72. See page 74. It's very important that you learn to become a pleasant person. One of the easiest things is to keep up with the people who attend worship. Usually, when the Holy Spirit does his job and begins nudging people back to God, they start the journey in a worship service.
Most churches have far more people in worship than they do in small groups.
This makes an excellent fishing pool for small groups. You might have your group sit consistently and strategically throughout the auditorium to look for new people. Many people will not fill out any kind of registration card, so you cannot get their names from the church's database. If your group is spreading out throughout the auditorium, they can notice when a newcomer comes to their zone. Some will turn in their names and these make ready prospects for your class.