<p>On this one, I agree with collegealum314. 
To expound on point #3, based on my observations of my friends and what I have heard from professors, if you get at least a B average (4.0/5.0 at MIT) and have strong research experience and recs, you will get in somewhere good.</p>
<p>One thing I must point out to you, OP…stop referring to HYPSM as “the nation’s top grad schools”. There is no such thing. What matters is the strength of the department. And the rankings in all subjects are not “HYPSM at the top, others below”. If you’re a chemical engineer, for instance, U of Minnesota is top 5, and much better than Harvard and Yale. If you’re aero/astro, Purdue, UMich, and UIUC are ahead of any Ivy. If you’re a creative writer (unlikely for an MIT prefrosh, but I’ve known a couple), Iowa State beats all of HYPSM.</p>