Illustrator and painter Sterling Hundley has an informative video showing his creative process.
Here are the 9 steps:
1. Start with text. Research.
2. Simplify the text into several words. Establish word stacks from these disparate ideas. Boil it down to several words that directly relate to the author's content.
3. Write down word associations under each word stack. Pursue tangents and even create new word stacks because this often leads to less obvious solutions.
4. Create simple icons next to your words. This is the first step in creating a visual connection to the literal associations. Keep it simple with little detail.
5. Form bridges—connections between the icons in separate word stacks, using metaphors, analogies, visual and literal associations, word play, shape, design, puns, etc.—and begin drawing.
6. Develop more complex drawings from the bridges. Juxtapose two disparate ideas into a single image.
7. Use value to fully explain shape.
8. Draw a box in correct proportions and define the composition. If an idea doesn't work in the prescribed confines, save for future use.
9. Define the method of execution as a compliment to the content solution.