As everyone says, a character's goal drives the story forward. But my main character has pretty much everything someone her age would want. She's fifteen, she's pretty, popular, has good grades, etc. A big part of the story has her forced to join a school organization she doesn't like (involves computers), and there's a bigger story going on, but she needs a personal goal. Her former best friend and crush are in the organization with her, but she has no interest in the former and I don't think having her pursue the latter is enough. So I was wondering if anyone had any suggestions on what I could do.
The most obvious answer is that people don't have everything. There's usually something everyone lacks, and a 15 year old is certainly no exception. It doesn't need to be something missing, it could be a subtler dissatisfaction, a certain loneliness, lack of fufilment or anxiety. People often don't entirely know what they want, and they don't have to be unhappy because of strong rational reasons. Any which way, you have to sweat the details for a MCs notivations, because it's going to be a large part of the story.
She wants to get into Harvard. She wants her parents to lay off on getting her into Harvard. She wants to transfer to the performing arts school. She wants to play Marian the Librarian in the fall performance of The Music Man. She wants her father to stop drinking. She wants her mother to throw her alcoholic father out of the house. She wants to get a Himalayan Blue Poppy to bloom. She's adopted and wants to find out who her birth parents are. She wants to get her (abusive, unknown to her) grandparents back into her life after they were cut off by her parents. She wants her parents to let her brother come home from military school.
Experience. No 15 year old has a whole lot of meaningful life experience, especially someone so privileged.
It needs to fit in with the main story. It's not something separate. My character wants to change the world. But it's not until she's gone through the all the things that happen that her goal gains real meaning. The little things she wanted to change became unimportant when the real problems revealed themselves. You have a character that all she seems to care about is good grades, being pretty, her "crush", that's all petty teenage angst. She needs to grow up. Life is wonderful, la-te-da, then something happens to shake that world up and all of a sudden (or maybe gradually) none of that seems important anymore. Thus her real goal reveals itself. Take those goals @ChickenFreak listed and pick one or more that can either evolve, or can evolve into something else.
Her mother is a compulsive hoarder and she spends much of her time hiding that secret. Her grandmother is dying. Her mother is clinically depressed. Her brother is suicidal. All she really cares about is becoming a singer/dancer/painter/Olympic gymnast, but it's becoming apparent that she's not good enough.
All that is in the area of identities. What is the essence of her self? What are relationships between identities and essence? Google Hauge identity essence.