Along with your grades and entrance exam scores, the Statement of Purpose is the only other piece of information a university will receive about a student. It is up to you to set yourself apart from the scores of students with excellent test scores, in around 700 words. No pressure or anything. While it's important to avoid the cliched "I want to help people", it's important to

a. convey your enthusiasm towards medicine

b. demonstrate what you have done to further your passion towards the discipline and

c. display the unique skills you possess that would make any university lucky to have you.