For the next part of the tutorial, you'll need to create the Width Profile, 1 and 5 brushes from my Width Profile brush tutorial.
Create a New Layer and rename it "Fur." I'm going to be using the Paintbrush Tool (B) with the Width Profile 1 brush, stroke color off black, and Opacity of 50%. Use this to draw the fur around the edges of the letters where the shapes are off black.
Modify the length of your strokes to the fur type of your dog. As Poppy is a short haired dog, the fur rendering will require short strokes. Consider the area of fur each letter represents and the direction the fur will be going.