With today’s digital tools, it isn’t necessary to dirty brushes or spend hours on hand illustrations. I often retouch and compose photography, and then apply painterly filters and effects until the right feel, tone and stroke is achieved. I find that rendering a 3D object with the lighting and perspective I want first, makes for very good conversions to illustrations, sometimes using post-processing 3D-to-2D plugins.
Some products I’ve illustrated:
Desert Oak Furniture
MetalCraft Tire Thumpers
Pacific International Pipe
Bushwacker Fender Flares