“I didn’t have the time to write you a short letter, so I’m writing you a long one instead,” Mark Twain is supposed to have written on a postcard to his friend. Good writers have always known that distilling one’s thoughts into a limited space takes effort and skill. (Bad writers sprinkle around lots of footnotes and pretend they’re not included in the word count.) So it must be immensely frustrating to whittle your life story and all your aspirations into about 600 words, only to find that the recipient has merely skim-read them. That’s the experience of students writing a UK university application personal statement – limited to 4,000 characters – which harassed admissions staff now only spend about two minutes reading.

I sympathise with the students, who are obliged to waffle on about all the hobbies they’re expected to be beavering away at while simultaneously studying for A-levels and probably holding down a part-time job. But perhaps universities are teaching them a valuable, if brutal lesson. Two minutes’ attention from a time-pressed stranger is a luxury that they will seldom enjoy in adulthood. It’s also more than enough time to read 600 words. So, if they can’t sell themselves in a short essay, how are they ever going to get anyone to open their emails, read their Tinder profiles, or pay attention to their strongly worded complaint to the British Airways customer services team? At what age is it appropriate to learn that everyone else is just too busy to listen to you selling yourself?

Increasingly, in an age of intense competition and instant communication, life is all about nailing the elevator pitch. Once they graduate, these poor students may be expected to “form a connection” with potential landlords by sending a letter spelling out all the ways in which they’d be the perfect tenants (top tip: boil it down to “I’m minted”). At job interviews, they’ll be asked to “talk about a time when [they] demonstrated effective communication skills”, and to do it in the most formulaic form of uncommunication ever devised by an HR department. Or perhaps they’ll write a book – 70,000 words of nuance, drama and research – and have to pitch it to a literary agent who has a hundred other pitches in her inbox. “It’s Joe Wicks meets Richard Osman,” they’ll say. A small part of them will die inside.

It’s important they also realise, though, that it is necessary and sometimes revolutionary to be able to grab someone’s attention and engage with them on a subject that matters. And that sometimes the best ways of doing that are the most succinct. “For sale: baby shoes, never worn.” was apparently written to win a bet, but the most successful tales of recent times are shorter still: “Make America Great Again”; “Take Back Control”; “Stop the Boats”; “Yes We Can”. The side that wins any debate is the one that tells the best story, and usually the one that tells it briefly.

When advertising copywriters do this, they understand that you must sell the sizzle, not the sausage. They describe solutions, not products, by showing the customer an image of what their life will look like when all their problems are solved. In other words, what successful pithy writing needs is empathy: the ability to put yourself in the shoes of the person reading it. “Good breeding consists in concealing how much we think of ourselves and how little we think of the other person,” Twain also wrote. And that’s a good lesson for anyone to learn.

• Katy Guest is a writer, reviewer and editor