Thom Rainer lists some ways that churches with older congregations became younger.
You could probably guess this one:
They were willing to change. There is a natural tendency to resist change as we get older. Colloquially, it is often expressed as “getting settled in our ways.” I spoke with one 77-year-old man who made a visit to the church in town that was reaching young people. He saw what attracted those younger generations in contrast to what was taking place in his church. He prayed that God would give him a heart that was other-focused instead of me-focused. He would later become a leader of the older congregants urging them to let go of things that were simply their preferences.
What other things can you imagine that would help an older church become younger?