<p>Typically, the most important factors are:</p>
<ul>
<li>good grades and/or class rank…</li>
<li>… in the most rigorous available course work at your high school, and …</li>
<li>… good test scores</li>
</ul>
<p>At the most selective colleges, extracurriculars and the like are definitely used, but only those who have the academic credentials will get that far (unless they have “hooks” which are mostly things one is born with, other than becoming an athlete that the college is interested in recruiting).</p>