I've got training as a graphic designer working with Illustrator & Photoshop - the whole skin-making thing is a quite involved process.
I paste and blend elements from photos of skin, use different brushes with skin texture patterns, and paint with highlights and shadows on different layers, all inside a deformed grid/UV Maps that fits onto the 3D Genus head.
The HUDs are easier, you get all you need in the developer kit from Genus. I build a prim and drop some ready made scripts in it, have no clue on how to write scripts/program. Then I have to make a nice texture to put on the box/HUD, at the moment my HUD for this skin is just some white squares - lol