This is not necessarily directed specifically at you, and I am not in any way claiming to be an expert writer, or even a good one.
But, seeing as I was able to catch a good number of readers' eyes and received positive comments on the written portions of my app, and spent a good deal of my undergraduate education reading and writing essays, I will offer some general advice on writing process.
The first thing you should do: Figure out how to answer the question, which is "Why do you want to go to medical school." The question is not why does some hypothetical third person want to go to medical school; it's
you. The question is not why do you
need to go to medical school much less why you
deserve to go to medical school; no one
needs to go to medical school and the rest of your app will speak for itself.
Second thing: What kind of app do you have?
@vrazzles, you have already identified a pretty solid theme. Here is the thing I care about, here's why I feel a medical career is the best way for me to pursue this passion of mine. Not every PS needs to be like that, but it's certainly a very credible angle (and not too different from the angle I used). I like to think of the PS as the glue that binds everything together. It's most likely the first or last thing anyone will read and probably the only part of your app other than the secondary anyone might ever bother to read more than a single time. The PS should therefore tie the app together, both summarizing and organizing it: what are your key strengths and motivators? what are your stand-out characteristics and achievements? can you credibly communicate -- or, at least, artfully reconstruct -- some rhyme or reason for why you spent your pre-med years the way you did, whether that was just 4 years of UG or 12 years of a very winding road?
Third thing: Write the thing. Just write it. It's going to be bad. The key to good draftsmanship is to get the first draft out as quickly as possible so you can start to tear it apart. Editing and critique are much, much easier than writing. That's why it's easy to make snarky comments on the internet about cringey, sophomoric writing from strangers but very hard to actually write your own PS when it comes down to it.
Fourth: step away from it. Don't think about it. Get some distance. At least 24 hrs. Hand it off to some trusted colleagues, friends, mentors if you feel confident enough to do that after just the first draft (I didn't because I am insanely self-conscious about my writing).
Fifth: Rewrite.
Repeat 3-5 until you have something you are proud of. To paraphrase
@Med Ed, it doesn't need to be Didion, but it can't be disqualifying. It's not a hard bar to clear, but that doesnt mean you should blow it off. Do your best on the PS and writing the rest of the app and the subsequent endless secondaries (which you will not have the luxury of rewriting endlessly for months before submitting) will be much easier.
On the subject of Didion, I think it helps to read some quality prose while trudging through the muck of your own amateur writing process. The last time many pre-meds had to write a proper essay might have been high school, god knows when was the last time they sat down and read one. Go to the library and read a few excerpts from Joan Didion's
White Album or
Slouching Towards Bethlehem, pickup Lewis Thomas'
Notes of a Biology Watcher, leaf or scroll through the latest issue of
n+1 or the
Baffler or the
Paris Review; pick your favorite subject and read a few literary essays on the topic by the real professionals. Get a sense for how to properly turn a phrase, move gracefully between anecdote and analysis, end a paragraph, vary syntax. Art is imitation and if you get even 0.1% of the way to imitating Baldwin in your PS, you will be well on your way to putting your best possible foot forward with the ps.
