Create a villain. Action comics usually focus on an epic battle between good and evil, so having a good villain is key. Your villain could be a ruthless profiteer, a power-hungry madman, a brilliant criminal mastermind, or anything else you can think of. He should have a striking appearance, and perhaps a good costume as well.
Design a nefarious plan. What does the villain hope to accomplish, and how?
Invent a hero. Heroes come in all types. Some draw on extraordinary physical prowess or super-powers others use powerful intellects, and still others use high-tech gadgets. Some heroes are very public figures, while others are secretive loaners.
Decide where your hero is coming from. Is she stopping the villain out of a sense of duty, a desire for vengeance, or simply an interest in unraveling the villains twisted plans? What is her history? Why does she fight crime in the first place?
Create a love interest. Although your action comic does not need to have one, most do. It adds another level to the struggle between the villain and hero.
Write a plot summary. Briefly outline the major events in the story.
Write a script. Describe what happens in every frame on every page. Include dialog and sound effects, as well as descriptions of the characters and setting.
Draw a rough sketch of the first page. Block in the layout, showing the position and orientation of characters, buildings, and other major objects.
Fill in the details with a pencil one panel at a time. Include every visual detail you want on that page of the comic.
Repeat steps 8 and 9 until you have a rough copy of the whole comic.
Ink and color the comic. Trace over the pencil lines with a pen or brush using black India ink. Add any shading you might want. Then go back and add other colors with paints or ink pens.
Add the dialog and sound effects. You can scan the comic and add dialog using a computer, or write in the letters by hand.