Use your own voice and your own stories to illustrate why you would be an asset to the school.
Don't fall into the trap of sanitizing your speech and your opinions for risk of offending an admissions officer.
Use outlines, word clouds or free association to help you come up with material for each of the different prompts.
Unlike the rest of your application, which consists largely of objective facts like grades and test scores, your application essay allows you to truly showcase what makes you unique as a student and a person.
You don't have to pick a strictly academic story for your essay; college admissions boards care about your complete persona, not simply your academic history.
However, remember that your story exists to serve your prompt; avoid telling a story for its own sake.
If you feel that you're overusing a particular word, think of alternatives on your own without consulting a thesaurus; using words that you're familiar with will help you avoid misusing them.
Your college essay should reflect your authentic speaking voice, but that doesn't mean that you can write it like a lengthy text message.
Leave out elements that aren't relevant to the essay, and resist the urge to include every single juicy detail.
When searching for stories from your history, choose incidents that allowed you to learn and grown.