98.5% of applicants in America will think that since you're allowed 4500 characters, they're expected to use as many of them as possible to compose the most formal, official-sounding piece of writing they can put together. Nothing could be further from the truth.
As others have said, you're not writing the great American novel here. Your goal in writing a personal statement should be exploiting your one opportunity to add an extra dimension of personal character into your application. In other words, this is likely your only chance to put something in your packet that will distance you from the thousands of other faceless applicants whose packets you're in a pile with. That means you've got to make it count.
Remember all the stuff you learned in high school composition? Like it or not, this is where it all comes home to roost. Here are some things to consider when writing or editing your personal statement:
- Spelling & grammar count: If you don't start by getting these right, none of the rest matters because nobody will read beyond the first few sentences. The good news is that these are pretty easy to address. The bad news is that while you can't count on good writing mechanics to get you admitted, you can count on bad writing mechanics to get your application thrown in the trash.
- Don't waste words reciting your CV: Your transcripts and extracurricular activities and shadowing hours and such and so on are already listed in boring 12-point Helvetica somewhere else in your packet. They already know all that stuff; why would you waste everyone's time saying it all again?
- Brevity is the soul of wit: 4500 characters may be the number you may use, but I can practically guarantee it's not how many you should use. You want the highest signal:noise ratio possible for this essay, and every extraneous word you include impedes that goal. My application essays for dental school and my first residency were roughly 3500 characters each; the essay for my current residency barely made it to 3000. If you're over 4000, you need to take a hard look at your statement in search of fat needing trimmed. Once you've written a draft, scrutinize it to find ways to tighten up the character count without sacrificing the narrative. Delete words, reorganize sentences, and experiment. The goal here, once you've written down the story you want to tell, is to streamline it in order to waste as few words as possible along the way. Hell, I'm even revising this, a stupid message board post, in order to increase the punch-per-word it delivers.
- Be yourself: Just as you should be yourself when you interview, you should be yourself when you write. If you don't often write formally, don't try to make your essay some sort of stuffy black-tie event. Remember how much you hated reading The Scarlet Letter in high school? That's exactly how the adcoms are going to remember your essay if that's how you write it.
The personal statement is your opportunity to show the adcom you're more than just a GPA and DAT score. It gives you a blank canvas, no rules, and one goal: giving the adcoms a reason to like and remember you. Don't let it go to waste.