Start with your favourite photo.
Consider what the important features are . Then consider what detail and size you want for the design. Scale is an important consideration in determining the amount of detail to be included. In this case, the head of this 10 week old puppy holding the toy was considered the aspect to work with -- the rest of the photograph really doesn't contribute to the design.

Change the toy for another object, in this case a plastic dumbbell, was the
choice made here. The coloring and shading were blocked into simplified shapes. The eyes were enlarged like they often are in cartoons, or Manga drawings. This is where artistic licence comes in to create the look and feel desired.
The design is digitized with computer software to define all the colors, textures, thread changes, and size of the final design.