A playwright’s advice on pairing up characters

If you start writing and suddenly it isn’t going where you want it to go, what you expected to happen can’t happen, and you are within five pages of your second-act curtain and you’re stuck, there is a procedure which I have found invaluable. I make a list of my principal characters and check to see if each character has had a major scene with every other character, and by “major” I mean a scene in which they are in conflict and explore each other. I found the third act for Young Love that way. I was hopelessly stuck and then discovered two people I had never had together in a major scene. Instantly values emerged, the scene broke, and there was my third act. I would say a good play, all other things being equal, should have thorough exploration of each other by all the major characters.

—Samson Raphaelson, The Human Nature of Playwriting