A time ago I never existed
Outlining
My design process for vector tracing starts off with outlining my image using bright noticeable colors. I keep colors separate or the same depending on the depth, or segment of my subject.
Layering check
After all of the outlines have been created, I swap the stroke color to be its fill color instead so that I can clearly visualize the layering of my current trace.
Single shade cutting.
After layering has been corrected, I begin to cut out the most prominent shades of my subject. I keep it to only one to two depths of shade to prevent the final design from seeming like an attempt to be 100% accurate.
Final design
After coloring has been set for all segments, I typically add a new background with contrasting colors that either combat the subject, or compliment my subject.