... and continue adding colour over your base colour, as well as gradually adding more fur detail!
The detail isn't talked about as much in this tutorial because I believe artists want to go straight to the detail too fast before they work on depth of base colour and light/shadow. So when adding fur detail, make sure you are happy with the base underneath. Does the base look shapely with features? or just flat still? Build with solid colours, occasionally blend, and then make your brush tip smaller as you work. You can also jump from several brush sizes while working on one spot! Then you'll be able to finally add more 'individual hair' without it looking empty (or killing your hand from drawing millions of hairs xD).