The supplement I sent had some grammatical mistakes and a biologically incorrect and weirdly used exaggeration. I feel like that might have contributed to my being wait listed… Also, would retaking SAT subject tests help? My SAT Physics is only 740 and Lit 730, Math II is 800. I think it may be below the top 25% of Princeton’s accepted students’ SATII range.
It is highly unlikely that your SAT subject test scores and a couple of typos were the difference between acceptance and waitlist, so no to both your questions, IMO.
I’m sorry to hear about your situation. This illustrates the importance of having numerous individuals look over all of your materials for submission. There are plenty of communities online where excellent writers gather and I am certain you could find proofreading help for free. Unfortunately, I think you must file this under “should’ve done.” Do not retake any tests: you are past that point and it will not help you (for instance, I had lower SAT II scores and that did not prevent me from being accepted right off the bat; if that were to work strongly in your favor, it would have already done so).
You could consider writing a letter. DO NOT mention your scores or grammatical mistakes (and do not paraphrase/bring the other materials into the letter). Be absolutely certain that the letter is free of such errors. Do not write more than one page, complete with proper headings, etc. You can Google “how to format a formal letter.” Address it to Dean Rapelye using proper formal title and salutation. Do some soul-searching; why is Princeton your top choice? What will you contribute? Why would Princeton be grateful that they reconsidered your application? (for the lattermost—do not state this explicitly as doing so will undermine any humility or credibility you are likely to demonstrate or gain in this exercise).
Beyond that, I would accept the hand you’re being dealt and play the game to the best of your ability. Think about it this way—if you don’t go to Princeton, your UGPA will almost certainly be higher than if you had, which will be useful after college. Many of us end up wishing we’d gone somewhere with inflated grades when applying to law school, etc.
@nicoleh625 My primary other choice is Cornell Engineering, which supposedly has the most rigorous engineering curriculum in the ivies, so I think I should be fine with Princeton. 
Thanks for the advice, though! I expected rejection so I didn’t try my best, which is my regret.