Do you want to see some new faces in the congregation? Plan for the church school to participate in the worship service. Many times, non-Adventist families send their children to the church school. Since their kids or loved ones are participating in the church service, they will be encouraged to attend church to support them.
Pro Tip: Have the kids participate throughout the whole service. Sometimes if the kids are freed early on, the families will not stay for the remainder of the service.