There should be a minimum of three images in your sequence, five or six would be better.
You will have to plan out the shots and pose your subjects so the story works.
Do NOT rely on speech bubbles or other objects to tell your story, make sure your poses are clear.
When you take your silhouette photos aim for backlit subjects to make high contrast silhouettes.
Use studio hot lights with two lights aimed at the background and turn the room light off to get more shadow on the subject(s). Meter for the background.
Shooting in front of a neutral background will help you get good images.
Make sure images are well focused and not blurred. You will need crisp edges for your images to look good.
You can edit photos in Photoshop to give them more blacks and whites, and contrast. (see the video below)