Decide on a theme. Whether you are using already created work, or you are creating a whole new body of work dedicated to this coloring book, stick to a theme. You might want to choose a particular time period if you are interested in history, create fantastical worlds if you like science fiction or fantasy or you could focus on a particular subject such as mandalas or animals.
Sketch your art. Keep in mind as you draw that you must leave enough white space between your lines to allow for the users of your book to fill it in with their own colors. Although more experienced colorists may be able to fill in the fine details of a graphic novel, most children need a greater amount of room to explore. Also, a child's fine motor skills may not allow for shading and small nuances of character in each drawing; their tools -- markers, crayons -- are often equally as unrefined and intended for broad strokes from small hands.
Outline your finished drawing with a felt pen and erase unnecessary pencil marks. This leaves clean and apparent white spaces within each image for budding artists to color each area with ease.
Scan your images. Set your scanner to scan in black and white to avoid faint remnants of erased mistakes. This will allow for a cleaner picture and make it easier for printing and coloring later. It is recommended that you number each image in the order you wish to publish them to create your pdf file within a short amount of time.
Arrange your images in a pdf file using such programs as Google Docs or similar free programs. Depending on the program, this process could take a matter of minutes should you use software downloaded to your computer or hours if you must upload each image to the program itself. Most pdf programs will allow you to either add images one at a time, placing them in the order you wish, or can accept a complete list of files to compile into a single pdf by selecting the numbered files from your chosen image folder. For instance, in Google Docs, the program works as a word processor, so you need only add images in order and save the whole file as a pdf, inserting page breaks between each image.
Save your pdf and scroll through to make certain that the images are in the order you wish them to be. Rearrange as necessary using any insert or tool menu your program provides. Check the image quality of your coloring book by printing pages. On most programs, select "File" and then "Print." A dialog box will appear, allowing you to select all or only specific pages. Test your drawings by selecting at least three images at random to print. If you are satisfied with the quality, move on to the next step. If not, you will need to rescan your images at a higher dpi (dots per inch); 300dpi is a minimum recommendation for good quality images. Saving images with the .png extension may also improve images with words or fine details.
Upload your finished coloring book to a website or host server and link to it on your website, blog or social networking page.