What will make me stand out from other candidates also applying for medical school?

Most importantly, that you showcase your personality and transfer this to paper. They want to see that you are well-rounded person and not just academic. This is because Medicine isn't just about 5/6 years of learning and then you're a doctor. It's about a life long journey of learning and balancing things you enjoy. They want to see that you've made a conscious effort to give something back to the community, and that you are an empathetic person, someone who is relateable, who has a passion to help the community and not do medicine in the name of prestige. Write something different, maybe a rhetorical question, not just "I am a hard working person, and I like to help people." Why do you want to help people??