Make it relatable. Do not let the character get handed a hundred dollars to go shopping at the mall whenever she wants. Do not let the character sleep over at her boyfriend's house and her parents are fine with it. Do not let the character have unprotected sex and not get pregnant (okay, that happens sometimes).
The character should not have all the money in the world or all the friends and the looks. Why can she not have enough money to get by? Why can she not have any friends or like, one? Why does she have to look perfect? Does anyone look perfect? The more relatable the better.
