Lot of writing is unrealistic (“fantasyland”) cause it doesn’t engage with the realities of class. Important when you are writing a character to decide — is this character rich? Poor? Middle Class?
If character is rich, have the character have a lot of promiscuous sex in rooms with a lot of shiny metal. Have them have, if a woman, a dress that shows her back muscles. If a man a suit. Have the character curse a lot and have large ingots of precious metals — in the pocket of suit (if a man) — in a small clutch purse (if a woman).
If character is poor, have character have a lot of promiscuous sex in rooms with no furniture or cinderblocks or on a dock. Have the character curse a lot and use cool slang. If black the character could be a rapper or perhaps sell narcotics. If latino could be a maid or sell narcotics. If white could have poor dental hygiene, scrappy, lots of kids, bad car.
If character is middle class should be spend most of time worried about being murdered or mugged by poor characters or fired by rich characters. Should have very little sex and be interested in dogs and/or watching shows on netflix.