I tend to do my sketching and inking by hand, then I scan it in to clean up my lines and add color. The bulk of my art referencing happens when I am not at my computer, but since my comic is about my dogs, they end up getting looked at far more than they want. One dog is pretty straightforward, but the other has color patterns that ALWAYS require referencing. X-D
(I imagine he is thinking, "Dangit woman! Don't you remember what I look like by now?!?")