Either zenethal highlight with thinned Yriel Yellow from a downward 45 degree angle or glaze in where the light would hit.
Recess shade with Iyanden Yellow thinned with Contrast Medium 1:1. Don't be too neat, the contrast should pull towards the recess and give something like a transition. Now is also a good time to paint the under-suit/tubing by your preferred method.
Recess shade everything again, this time being careful, and using thinned Mournfang Brown .
Selectively recess shade with thinned Rhinox Hide , aiming for the very deepest parts.
Add a chunky highlight of Yriel Yellow to all edges. Alternatively, you can mix a vibrant yellow like Flash Gitz Yellow with the Averland Sunset from earlier.
Edge highlight everything again with Yriel Yellow and Screaming Skull mixed 1:1.
Selectively edge highlight the most exposed curved edges and corners where highlights meet with Screaming Skull .
Add dot highlights of a pure white like Dead White to the centre of the previous highlights and points/corners.