Create a dedicated file folder for your comic book. Create subfolders for reusable art resources and archived issues of your book (if it is a series). Place a shortcut to the main folder on your desktop.
Create a new image file in your editing program that is set to your preferred page size. Set the dots-per-inch quality value to 360 (any higher won't noticeably improve quality). Draw panels if you plan to have them set a certain way on most pages; otherwise, leave it blank. Save the image as a template for all future pages.
Scan in hand-drawn art or draw directly into the program with a digital drawing tablet. Use thin sketch lines first, including for panels---better to erase basic shapes than any substantial art. Opt for overlap in the art and erase as needed. Allow room in the art for speech bubbles. Drop speech bubbles into the space.
Insert the dialogue into the speech bubbles. Re-size the bubbles as needed.
Colorize the art using the color fill tool in the program. Add effects like shadow or light gradients to bring depth to the color.
Save finished pages to the appropriate issue folder as separate JPEG files. Name them by book title, issue and page number.
Publish the comic book to electronic or print format. Convert the issue folders to a ZIP archive and rename the extension to CBR (Comic Book Reader format) to make the issue viewable in a sequential image reading program. Convert each JPEG page into a PDF file and send to a mass printing company to turn the issue into a physical book.