In my church this month the congregation is singing Christmas carols fifteen minutes prior to the service beginning. Two of my students, who attend the same church, are playing carols with me as accompanists. They are new to this skill and I have been singing with them to help them learn to follow another musician. Will they play perfectly? Probally not, but the leaders of this church understand the need to groom the next generation of church musicians. Abiding a few mistakes is a small price to pay for the huge reward of having volunteer, amateur pianists ready to assist a group and to provide music.
You may have other musical venues to train your students, but I see the most consistent place, for those students who are in my church, is the prelude and postlude times in church meetings. They are not in the spotlight and I "break them in" as duet accompanists with me. Then later I can assign them a time to prepare music for the entire prelude or postlude period.
I am a volunteer organist and am very vocal about music. Those leaders who organize music see the wisdom in my requests and I have support from them and from their parents.
I can give credit to my responsibility as a church musician for my staying active in piano lessons for ten years. These opportunities to use my skill made me practice.
