Outline the story arch. Tim Crook, Head of Radio at Goldsmiths University of London, suggests the format of set up, struggle and resolution. This is another way of saying a radio drama needs a beginning, middle and end. Drop listeners directly into already on-going action. Make listeners wonder what is going on. Sparking interest and keeping an audience listening is the main goal. This all builds up to the main point of conflict. A drama does not exist without conflict. The conflict is what drives the action throughout the story. The majority of the drama should consist of the set up and struggle with the resolution taking up about a quarter, or less, of the time. Keeping the script around 30 minutes helps retain listener's attention.
Draft character sketches. The characters carry the action of the drama. Characters must be relateable, especially the protagonist. The audience must relate to the protagonist and care about what she is doing. The antagonist must somehow threaten the protagonist. When thinking about characters, make sure that both positive and negative characteristics are added to each. Protagonists are not entirely good and antagonists are not entirely bad. Creating contradictions allows for more drama, conflict and realistic characters.
Pick appropriate music and sound effects. Radio dramas rely heavily on music and sound effects to portray atmosphere and feeling. The right music will indicate tension, peace or a humorous situation. Just as in a screenplay, music can drastically alter the feeling of a scene. In radio drama, sound effects can indicate the entrance or exit of a character. They can give clue to the setting of the scene. Car honks reveal a city setting while bird chirps indicate a country scene. Make good use of music and sound effect as they are essential to radio dramas.
Focus on dialogue. Just as important as sound effects and music, the dialogue will carry the action of the drama to resolution. Dialogue must be sharp and precise, with no superfluous language. Dialogue can provide opportunities for humor, conflict or musing. Each character must have a unique diction that is hers alone. Especially in radio drama, listeners should be able to pick out a character not just by voice quality but also by what the character is saying. Create language "ticks" for characters that create individual voices. Let characters react to the action in their own way.
Format the script professionally with clear cues. Proper formatting allows the actors to easily read and perform during the presentations. Keep formatting consistent throughout, otherwise it can get confusing. Use page headings and numbers for easy references during practice. Cues are audio elements of dialogue, music and sound effects. These elements are strategically placed throughout the script and may even be accompanied by a physical cue from the director. Numbering the cues will make rehearsals run smoothly by quickly directing everyone to the same point in the script.