The singers all loathe the sight of one another, the chorus despises the singers, they both hate the orchestra, and everyone fears the conductor; the staff on one prompt side won't talk to the staff on the opposite prompt side, the dancers are all crazed from hunger in any case.
Terry PratchettOnce you have your character sitting right there in your head, all you really need to do is wind them up, put them down, and simply write down what they do, say, or think.
Terry Pratchett