I play my EC along with the radio - usually the jazz station (WBGO) and occasionally the oldies station (WCBS). They choose the tunes, they choose the key, they choose the tempo. If it's a piece I know, I do my best to play the melody along with them. If I don't know the piece, or if it's too fast or in too difficult a key, I improvise harmonies. I've been doing this for several years and find I am making slow but steady progress with my playing. My goal is to become a good enough concertinist to sit in on local jazz sessions.