Now that we have the individual strands drawn in, it looks flat. To put the head of hair in a realistic environment, consider the source of light. Here, it is coming from the front/left, so we want to highlight the front and darken the back. We also want to highlight natural contours of the head and thin-ness of the ends of the hair. Here are the areas I've highlighted and darkened with a large (approx. 50 to 100 px) soft edge brush with dodge and burn. Try different dodge/burn modes to match your lighting source:- Dodge Midtones gives less saturated, whiter highlights- Dodge Highlights gives more saturated yellower hilights - Burn Midtones gives more saturated shadows in keeping with the base color- Burn Highlights gives less saturated, gray/black shadowsUse all in combination to achieve a more natural look: