One rule I did my best to follow at any radio station: I would promote the DJ following me on the air by sounding positive but not oversell his or her show. I've never been of the "Just wait until you hear so-and-so; (s)he's got three hours of the best tunes you'd ever want to hear" school. For all I know, the DJ about to go on the air after me might have a cold or the flu. If it's a station where the music was preprogrammed, I couldn't promote the DJ's song selection abilities. Even if it's a station where the DJs get to choose some or all of the music, that's a subjective call anyway. When signing off, I would just ask listeners to "stay tuned for so-and-so, who will continue the smooth jazz (or will bring you however many hours of another genre of music.)"
Asking listeners to stay tuned is the key.
