Choose a theme for the comic story and record it at the top of a sheet of paper. Themes are often life lessons that readers can apply to their real-life situations. Crime doesn't pay and good prevails over evil are well-used themes that comic writers like to take new slants on. Comic story themes can be as basic as pointing out the tedium of human existence.
Select one concise sentence that will relay the overall who, when, why and where of the plot for your particular comic story. Something like, "A young girl investigates her sister's unsolved murder in small town" or "Police officer gets shot and discovers that he is bulletproof."
Write down the names and brief descriptions of a few characters who will be a central part of the comic story. Write details about their background, style, physical appearance and anything you feel is important to the individual character.
Compose 10 or more character interaction sequences with dialogue ideas that relay the plot while giving information that establishes the characters.
Arrange the interaction descriptions and dialogue into an order that flows together to structure scenes and transitions. This is where the comic writer decides what level of control he wants to have on the final composition of the book. Some writers choose to give artists cell-by-cell guidelines for layout and pacing, while others choose to trust the interpretation of the artists. Make notes to give directions that are as detailed as you feel the artists will need to understand your perspective.
Give an organized version of the comic story transcript that is complete with theme, plot synopsis, character descriptions and dialogue to the comic artists and make yourself available for questions.