Choose a theme you can use to guide the overall composition of your statement. According to the Princeton Review, many medical school applications offer topics to consider when choosing a theme. These include describing a mentor or inspiring person who spurred you on to medicine or offered an insight into medical practice.
Relate past personal experiences to the study of medicine and describe, using concrete examples, how those experiences shaped you and molded you into a prospective health care professional.
Provide a well-rounded view of yourself. Studentdoc.com describes this as not "pretend[ing] you're the best thing since sliced bread." As you weave your theme through the essay and describe past experiences, keep a humble tone and avoid exaggerating details or embellishing. Discuss strengths and weaknesses; when describing weaknesses, describe what you have been doing to minimize them and how this will help you in medical school.