Writing Between the Lines
A few gems from SFSU playwriting instructor Robert Barker's talk on subtext, March 1999:
Subtext is all the statements that are not verbalized. Subtext allows the audience to participate in the creation of meaning, thereby drawing the audience into the play. Suspense elicits the question "what's going to happen next?" Subtext elicits the question "what's happening now?" If your play is a question, what is the question? If the question is answered, what is the answer? When all the questions are answered, the play is over.

Techniques for heightening subtext:

• Take a scene and cut dialog from it. Ask yourself "does this really need to be stated?"
  
• Have the dialog revolve around an object.
  
• Create characters with contradictions.
  
• Give the characters secrets.
  
• Let the audience in on secrets that the characters do not know. For example, in scene one Mary gets back a positive pregnancy test. In scene two she is with John, her boyfriend, who does not know Mary is pregnant.
  

Two exercises:

• Take a portable tape recorder. Surreptitiously record some real live conversations. Transcribe the conversations.
  
• Select two characters. Select an object. Select a place for the scene to take place. Now write a scene, but the scene is all action, no dialog.