In my setting, a city was founded by people from all over the world, and developed in almost complete isolation (long version here). The story in itself starts several generations after the foundation. All inhabitants of the city have mixed origins, but not enough time has passed for an “average physical appearance” to emerge.
When writing my first test scenes, I found myself describing in too many details the appearance of my characters. For now, my solution is to make the diversity of the city population clear early in the story, and to give only a couple of physical traits to each main character.
But I have the same problems with my crowd descriptions. They end up either full of purple stuff, too dry or just plainly awkward.
For example, I’ve tried describing skin tone with colors only, but it’s not very evocative. I’ve also tried comparisons, using minerals (copper, terra cotta, etc.), plants (wood, flowers, etc.), weather stuff (clouds, sea, etc.) or even food (chocolate, honey, etc.)...
It was the worst.
I just don’t know how to show the variety of skin tone, hair color & curliness, eyes shapes, etc.
What guidelines should I use to convey the image of a diverse crowd and to show the physical appearance of my main characters while avoiding purple prose and awkward comparisons?
EDIT
Quick translation of some of the descriptions I'm not happy with:
The stranger at the kitchen table looked up from her newspaper. She had a thin face splattered with chocolate freckles and flanked by two big round ears.
In the door frame stood a little old man with a closed face and hair like a storm cloud.
When Adda stepped on the deck, she was greeted by a sailor leaning against the parapet, sipping a bowl of coffee almost as dark as his skin.
Her long oiled hair made her look like she was coming back from a swim in the nearest canal. This impression was accentuated by the sweet and sickly smell following her.
He was a man of dignified attitude and slow gestures. His daughters and him shared the same delicate features, the same golden skin, the same brown freckles and the same thick black hair, but not the same ears. The girls had their mother’s ears.
A sentence trying to show the population diversity :
A fever of merchants and buyers filled the market place. Here, one circular look offered the full palette of all the colours, faces and hair métissage * could create.
* (Not sure how to translate it, mixing maybe?)