Introduce colours on different layer modes
Once I’m happy with my values I start applying colours on layers set to Overlay, Multiply, Color Dodge, Darken and so on. I try to vary my colours and pick new ones several times in the Color window. Because my character has yellowish skin, I use greens, browns, oranges, yellows and even some cyan. Then I drop my layers and keep on painting normally. Finally I draw some tattoo-like shapes on one side of her face, before flipping them to the other side. I consider turning these tattoos into custom brushes for later use.
Paintng with pattern brushes
I introduce a few designs using some custom pattern brushes. I create one by taking a graphic, transform it into a brush and then play around with the settings within the natural Brush media window (Brush tip shape> Spacing and Shape dynamics>Angle Jitter set to Direction). Such brushes are ideal for creating clothing patterns, tattoos and scales, for example.