People have lost their sense of community. In American culture today, a small group Bible study in someone's house is probably a much more effective entry point for a typical unbeliever than a worship assembly or a traditional gospel meeting. Many outsiders who would not feel comfortable going to a church building will accept an invitation to a neighbor's home. Growing churches, on the other hand, typically offer an ever-increasing number of small group classes. Instead of looking at them as a supplement to the work, they view them as central to a purpose that is strategically executed.
Some suggestions are in order.
Big programs always die. Sustainable changes must be made incrementally. Start small and grow naturally. When a small class of eight or ten people grows to fifteen or sixteen regular attendees, divide into two groups, and start the process all over again. Multiplication of groups must be self-sustainable, as participants themselves see the overwhelming value of this approach and are willing to voluntarily commit to it on their own.