<p>A “hook” is generally considered to be something special or unique about you (besides the standard academic and extracurricular stuff) that makes the college want you quite a bit more than the average applicant.</p>
<p>Stanford’s not particularly known for music, so being conservatory-level would probably be a big bonus. I believe the process for auditions and tapes is that your audition (or tape) is heard by one of the people who teach your instrument, who evaluates it, and the evaluation is then passed on to the admissions department.</p>
<p>What instrument(s) do you play? A bit will depend on that.</p>