Character is Key

Plays, fiction, non-fiction, poetry. What do they all have in common?

Character.

Character is key. As you noted in Streetcar Named Desire, if Blanche and Stanley weren't interesting characters (as well as Stella, Mitch, etc.) the play would not have been as significant. The action of the play revolves around their conflict and thier goals!

Character and plot work together.
Plays that involve characters in CONFLICT are better plays than ones that do not.

As you know from Fiction (see the Fiction lectures and notes on this website from the beginning of the year), characterization is necessary to develop character. Characterization includes the actions a character performs (a necessary element in Playwriting), what the character says about him/herself (often through dialogue, soliloquy or monologue), and what other characters say about the character in question (through dialogue - often when that character is not "on-stage", almost like gossip happens in real life.)

Characters are often products of their internal (inside/personal) life and thier external lives (their occupations, interaction with other people, their economic or social environment, etc.). These external and internal elements are used to create CONFLICT.

Characters have a need to speak in a play. Without dialogue, plays don't work right.

You should be intimately familiar with the following types of characters:

Protagonist
Antagonist
Secondary characters (minor characters)
Dynamic characters (characters who change during the story)

All characters in a play need to be there for a reason. It is your job as a writer to give them a reason!