Starting from a sketch, created on a digital tablet or by digitizing traditional artwork, is a great place to start with many digital illustrations. When composing and combining images in Adobe Illustrator and Photoshop, the choices are almost endless.
Creations built with images that combine colorization, manipulation and compositing can take a basic artwork to amazing levels in the digital realm. Merging photography, images, drawings, paintings and traditional media in digital format lets me create illustrations and artwork that would be impossible using only traditional or digital tools.
Digital technology has allowed everyday people to do simple image illusions and composites. The difference between simple and complex imaging skills become clear when you can tell images are "Photoshoped." Realistic and complex image effects and composites require professional level skills and expertise.
Being an experienced artist in painting, drawing and airbrush art, combined with over 30 years of using digital tools, makes me aware of those little things that make a real difference in digital effects. Understanding light, color, edges, scale and perspective takes digital effects from are "fun" to professional.