One of my most frequented websites, Digital Arts Online, recently showcased designs by digital artist Bruno Mangyoku.
I so admired one of his works (the last one the series on that website if I recall), that I thought it would be a challenge to make an attempt to reproduce parts of it, so I might try and learn from this graphic master.
It so happens, that I so enjoyed that task of examining that piece that I kept going .... and as I did, I felt my knowledge of Adobe Illustrator consolidated and expanded. Clipping masks really came to the fore. Also swatches - I used the defined colour book "desaturated" to replicate the muted palette. With really organic details, like the lips, using Blend Modes and Opacity really helped merge some of these muted desaturated colours.
The painting mode "within bounds" (analogous to Clipping masks) really helped with the glasses frames and the headphones. The Blob Brush was great to use within these bounds. With the headphones, as with the subject's jumper, the Shape Builder tool came to the fore, creating sub-shapes from taking the volume outline and dividing it by pen lines (Pen Tool).
The hair highlight details were created using the brushes I defined as detailed in "Jackie K" after Jeffrey Everett.