Characters see the world through the lens of their experiences.
Remember that peasant girl from the October 31 ‘Before Your Write’ tip? She’s the one who lived in Europe during the Dark Ages. I’d written a comment to myself to remember not to use a gem or ocean/sea simile to describe her eyes or the color of her hair or clothing. Why? Because where would she have seen any gems or luxury goods deep in the middle of agrarian, Dark Ages France? And when would she have ever had a glimpse of the ocean?
Due to her place in history and her personal experience, she has a very small set of experiences to draw upon to describe the world around her. For metaphors or similes, she’s limited to things she’s observed in her own village or the fields that surround it or things she’s seen and heard and smelled in the nearest country chapel. She’s seen birds and deer and wolves. Maybe a bear. There might be a stream or a river somewhere near. And that’s about it. No hair can fall over her shoulder like a length of satin. Nothing can gleam like a diamond. Clouds probably can’t billow across the sky like sails. The wind can’t whip the fields of wheat into waves.
See what I’m saying?
It’s not how you see your characters’ world. It’s how they see it.