I have a scientific method for creating character appearances. It's called. "The Random Method." Yes. That's what I call it. Think about it for a second. I've never seen these 'people' before. Therefore, designing their features is more 'out of the blue.'
I've discovered a funny thing. Sometimes, they actually resemble people. This is always totally unintentional.
There's also the lighting factor. Character appearances change in various lighting.
What? Didn't you spend countless hours laboring over what they would look like?... Uh. No.
I like this approach because, the writing process is a process of discovery. So, I'm introduced to these characters, and from there the writing unfolds who they are. Along the way, their 'inner characteristics' become more important than their outer.
Creating an imaginary world of people, especially when they are so realistic, is an interesting and sometimes complicated art. I need a hug.