We had a discussion about this in the Class of 19 Facebook page, and the one quality we all agreed on was that Stanford is looking for unique students with personalities. The classic Ivy League applicants who pump their whole app with academic ECs, mindblowing test scores, and sparkling transcripts are not as valued as students who do well in school, but also prove that they’re interesting, driven people. If you get in, you’ll get a handwritten note from the admissions officer who reviewed your application, and almost everyone I know had one that mentioned their unique personalities and dedication as one of the deciding factors.
Best of luck to you on the application process.