The beginning playwright is encouraged to accept the following guidelines to write the first play. Later plays can be more free. Indeed, deliberately breaking selected guidelines later will help you better understand the nature of dramatic writing. For now, however, let these guidelines help you in your initial steps toward learning the art and craft of playwriting.

1. Start with a one-act play. A full-length play isn't merely three times longer and therefore only three times more difficult. But that a one-act is easier doesn't mean it is insignificant. On the contrary, the one-act play can be exciting and vibrantly alive.

Starting with the one-act, however, lets the writer begin with a canvas that is easily seen at a glance, instead of a mural that covers such a huge space the perception doesn't grasp it all. The one-act typically has only a few characters, is an examination of a single dramatic incident, and runs about half an hour in length. It usually stays within one time frame and one place. Because there are fewer writing complexities, you'll be able to focus more upon actual writing and you'll have less concern about a number of stage problems which come with the full-length.

2. Write about something that touches your heart. Writing manuals usually tell the beginner to write "about what you know best." I think that can lead the beginner to think in terms of the daily mundane events. Better, I believe, is for the beginner to care; if the playwright is involved with the subject, that interest will pull an audience along.

3. Conflict is essential to drama. For your first play there should be conflict. Drama is the art of the showdown. Force must be opposed by force, person (or group) against person (or group), desire against desire.
If there's no conflict, the dramatic qualities are lost. The result may still hold the stage, but the odds against it are increased. More importantly, even if the one-act has no conflict and yet holds the stage, the playwright hasn't learned that all-significant lesson about showing conflict. You'll want to know that when you write more.

4. Let there be emotions People care in your first play, I hope, people feel strongly, whether it is love or hate, happiness or despair. If you are able to get them emotional, your characters more than likely are going to be active, going somewhere. The audience will care more about emotional people than they'll respond to those dull-eyed, unfeeling dramatic deadbeats.

5. Stay within the "Realistic" mode Realism deals with contemporary people the sort who might live next door, in their contemporary activities. Realism also involves the selective use of ordinary speech It avoids the aside and the soliloquy. It is quite comfortable inside the traditional box set. Realism is selective and sometimes critical, in its presentation of objective facts.
Realism is the familiar mode you've seen most often: it dominates television, and only a handful of movies break away from realism. No doubt you've also seen it on stage more than any other mode. Because you know it best, your first play will be easier to write if you stay in realism. Expressionism, absurdism, symbolism, epic: avoid these for your first time into playwriting.

6. Limit the number of characters. Too many characters and you may lose some: they'll be on stage but saying and doing nothing, so you'll send them off to make dinner or fix the car while you focus on the remaining characters you like better. Consider eliminating those who are dead.
Strenuously avoid "utilitarian" characters, those people who make minor announcements (in older drawing-room plays they say little more than "dinner is served") or deliver packages or messages (Western Union's delivery boy, remember, is as much a relic as the butler). Such characters tend to be flat, no fun for playwright, performer, or audience.
Some utilitarians are confidants, on stage to serve as ears so the protagonist will be able to speak inner thoughts without resorting to the soliloquy The confidant in this sort of case turns out to be about as vital as a wooden listening post.

Confidants, by the way, are easily recognized: their faces are covered with a huge question mark. They seem to be asking questions eternally, without any apparent interest in question or answer. The playwright uses the confidant to get to the answer. If such a person is necessary, let the human be more than a pair of ears.

Just how many characters should be in the play?

Three is a good number for the first play. The triangle is always helpful; three characters allow development of good action and conflict and variety. More, and there's the risk of excess baggage; less, and the characters may quickly become thin and tired.

7. Keep them all on stage as long as you can. All too often I've seen plays developing potentially exciting situations, only to be deflated by the exit of a prime character. The audience will feel let down: promised excitement evaporated through the swinging door.
The flurry of activity with entrances and exits is deceptive. There may be a feeling of action but in truth there's only movement of people at the door. The more such business, often the less drama.
The beginning writer needs to aim to keep all characters alive and actively contributing to the play's action. So, then, you need try to keep them all on stage as long as you possibly can. If you have a character who keeps running out, perhaps he ought be eliminated.

8. No breaks: no scene shifts, no time lapses. just as some playwrights have people leaving when stage action is growing, so also there are authors who cut from the forthcoming explosion with a pause to shift scenery or to indicate a passage of time. There is a break in the action and that always is disappointing. Such lapses all too often are barriers to the play's communication with the audience.

If you have in mind a play that takes place first in an apartment, then in a grocery store, then in a subway, you have let motion pictures overly influence your theatrical concept. This just won't wash, not in a one-act stage play: that calls for so many sets and breaks that producers will shy away from your script. (Yes, yes, you can cite this or that exception, but we're talking about a beginner's first play, not a script by someone with the established reputation.)

Reduce the locales to the one place where the essential action takes place, and forget the travelogue. So also with the jumps in time: find the single prime moment for these events to take place.

Later you can jump freely in time and space, as Miller does so magnificently in After the Fall. Your first play, however, needs your concentrated attention on action, not on inventive devices to jump around through time and apparent interest in question or answer. The playwright uses the confidant to get to the answer. If such a person is necessary, let the human be more than a pair of ears.

9. Aim for a forty minute play. One-act plays are delightfully free of the restrictions placed upon full-lengths, and can be only a few minutes long to something well over an hour. The freedom is heady stuff for a beginning writer.

Aim for around thirty to forty-five minutes. Less than that and you probably only sketched the characters and action; much longer, and you might exhaust your initial energies (and your audience!). Your goal, of course, is to be sure you achieve adequate amplification: too many beginners start with a play only eight to ten minutes long, and it seems full of holes. Your concept should be one that demands something over half an hour to be shown.

10. Start the plot as soon as you can. Let the exposition, foreshadowing, mood, and character come after the beginning of the plot (the point of attack). Get into the action quickly, and let the other elements follow.

11. Remember the advantage of the Protagonist-Antagonist structure. Our era of the anti-hero apparently has removed the Protagonist from the stage. Too bad. The Protagonist is a very handy character indeed, and the Protagonist/Antagonist structure automatically brings conflict which you recall is essential for drama.

The Protagonist is the "good guy," the one with whom we sympathize and/or empathize, the central character of the play. A better definition: the one whose conscious will is driving to attain a goal. The Antagonist stands firmly in the way. Both should be equal forces at the beginning of the play: if one is obviously stronger, the conflict is over quickly and so should the play be.
(If you do not fully understand the personality of the true Protagonist, look at Cyrano in Hooker's translation of Rostand's Cyrano de Bergerac. He is so strongly a conscious will moving actively that it takes several antagonists to balance Cyrano.)

12. Keep speeches short. Long speeches often grow boring. Sometimes they are didactic, the playwright Delivering The Play's Message. Always they drag the tempo. But the worst sin of a long speech is that it means the playwright is thinking just of that one character and all the others are lying about dead.

Short speeches, quick exchanges between characters, on the other hand, keep all of them alive and make the play appear to be more crisp and more vital. The play will increase in pace and you'll automatically feel a need to increase the complications.

How long is "short"? Let the dialog carry but one idea per speech. Or, to give you another answer, let your ear "listen" to the other characters while one is talking, and see who wants to interrupt. A third answer: try to keep the speeches under, say, some twenty words.

13. Complications are the Plot's Heart Beat. A play depends upon conflict for its dramatic effect, and complications are the active subdivisions of the basic conflict.

From: Writing, Producing & Selling Your Play by Louis E. Catron