The first two people she came across were the idiots she took the rock from; they walked along the same route to school. They'd already been punished, so she kept going, several people in mind as she approached the school. The first of them was Susan Johnson, a genuinely nice girl who, most importantly, did as she asked. She wasn't the prettiest girl, but definitely one of the smartest. She always helped Sarah with her homework, so she decided to make a little wish to help her out.
Brains weren't everything, Sarah thought as she walked behind Susan. Looks were. With this in mind, she made her whispered wish. "I wish you were beautiful - not as much as me, of course - and just as bright as an average person." There. That should do it, and the new knockout hadn't heard.
Sitting in her first class a few minutes later, Sarah surveyed the room, barely paying attention to the teacher; one she didn't know well, and had nothing against. But every time the teacher asked a question, the same snide voice answered: a boy named Louie, one she'd known since first grade, who was both the biggest geek and biggest pig she'd ever met. Most of his time not spent answering questions and lording his knowledge over everyone was spent staring at her, and the other cheerleaders.
She had the perfect idea for him. Sarah laid her head down on her desk, whispering into her hair, she made her wish... "I wish Louie would slowly turn into a geeky girl over the course of the day, and that he was fully aware of every change but he and I were the only ones who noticed them." Deep breath. "I wish that to everyone else, each stage of the change was as if he'd always been that." With that, she sat back and waited for it to begin.