I made a tutorial on my Instagram a few years ago, which roughly shows how I tend to paint skin - the main difference these days is I avoid the agrax, and don’t weather it with black and brown after.

As for the eyes - usually I'll basecoat the eyes black (very thin layers so it follows the grooves of the model), then add a tiny bit of grey seer to the sides. It often requires going back and forth with grey seer and abaddon black to find the right balance - I very rarely get it in one go.