My approach to writing these comics has been to have a focus, something the page needs to accomplish. Then, sketch a series of images which will lead to that focus visually. Then, add dialogue in places where the images wouldn't tell the whole story, if the focus is particularly difficult to draw, the image will be much smaller to make room for the required dialogue. To avoid drawing tiny characters, this usually means drawing scenery, or parts of characters so the sense of scale isn't lost.