After grammar and spelling, the next problem that needs be checked is transition. Read your essay. Go through it from end to end, and check to see if your essay flows smoothly. Does each sentence flow smoothly to the next? Does each paragraph flow logically to the next? Each statement should be connected or somehow related to the one before it, not thrown randomly together. Next, limit the use of "I" in the beginning of most sentences as it is already obvious that the essay is a piece written by an individual.
The reader of your medical school application is expecting a degree of proof and really wants to know how you know. It's not enough for you to say you want to help people. How do you know what you want to do in medicine, what have you done that leads you to know that? How to write your medical school personal statement: Persuasion The most persuasive way to answer this question is by sharing experiential knowledge. You would say to an admissions official in conversation, "I know because I've done it. That's how I know. And I can give a specific story."