A portrait study from Noah Bradley's reference pack, along with some process and tips
A couple takeaways:
-this yellow highlight is nearly white at the highlight and nearly orange-reddish near the edge, where there's subsurface scattering
-there's also subsurf scattering visible through the nostril from this angle
-the main light source is colder, so it creates grayer, colder highlights
-the main light source has falloff, which makes for a more dramatic effect
-there's a clear, blocky form change at the temporal bone, and a small plane change at the masseter muscle
-the ear casts a very small shadow, the neck muscles cast a large shadow
Hopefully that was useful, thank you!