Lana is a queen bee stereotype, and she is a constant bully to anyone not popular. In the book series that the film is based on, she becomes friends with Mia in the final books, supporting her relationship with Micheal.
Role in the film
Lana is a very popular girl at school.
At one point, when Mia (having found out that she is a princess) is wearing a hat, Lana reminds the teacher of the no-hats policy, much to Mia's embarrassment when she exposes her hair.
One night, at the beach, she and two of her friends remove the tent in which Mia is hiding in front of a paparazzi, which resulted in her being clad in only a towel and receiving a forced kiss from Josh Bryant.
A few days later, Lana and her friends see Mia and her classmate, Jeremiah Hart, and mock them. Mia then asks Lana if her cheerleading outfit goes well with anything, and Lana says it does, unaware that Mia was including something that wasn't clothing. As payback for the humiliation, Mia smears chocolate ice cream on her outfit. Lana tells Mia that she is such a freak, and Mia replies that she may grow out of it, but Lana will never stop being a jerk. The other students chant, "Lana got coned!" over and over, with Lilly Moscovitz joining in. When Lana tells Vice Principal Gupta about this, all she got was a suggestion to send the outfit to the cleaners.
In a deleted scene, her bullying Mia would have been exposed by a reporter.