To draw this picture of kitty catz, I started with a pencil sketch, inking in the lines I liked, then erasing the pencil marks. I used my beloved Prismacolors to add vibrant colors. In this drawing I put in the intricate lines of his fur after I'd added the color. This was difficult, because the tiny ink pens I used often clogged with the beezwax of the colored pencils.
I've discovered since then, the old fashioned ink pens with nibs, which are dipped into indelible ink. They can splatter, but sometimes the results of such a mistake can be wonderful. And they don't have problems when I use them to draw in details after the color has been added.