Good writing is lean and confident. Don't describe an event as rather spectacular or very awesome. Every little qualifier whittles away some fraction of the reader's trust.
-William Zinsser, On Writing Well
Comments: Almost every student makes the mistake he identifies: "Don't hedge your prose with little timidities." Words are strong. If you believe something deserves the word spectacular or awesome, tacking on "rather" or "very" weakens those words. This seems like a small point. But it's important. As Zinsser points out, you lose your reader's trust: "Readers want a writer who believes in himself and in what he is saying." That applies to a college essay, a sales email, a legal brief.
Specificity is Authentic
Specificity suggests that you know what you are talking about.
Example: “Don't get me wrong: I love the restaurant business. Hell, I'm still in the restaurant business - a lifetime, classically trained chef who, an hour from now, will probably be roasting bones for demi-glace and butchering beef tenderloins in a cellar prep kitchen on lower Park Avenue."
—Bourdain, kitchen confidential
Comments: Anthony could write. Study that paragraph. You can hear him, right? It’s not just the specifics. Look how he uses italics, a (slightly) edgy word like “hell”… he sounds like a human.
Sewer roaches, according to Terminex. Blattaria implacablus or something. Really huge roaches. Armored-vehicle-type bugs. Totally black, with Kevlar-type cases, the works. And fearless, raised in the Hobbesian sewers down there. These Southwest sewer roaches you turn on the light and they just look up at you from the tile like: 'You got a problem?'
—David Foster Wallace, Infinite Jest, 1996
Comments: Why is this good writing? What can we learn from DFW writing about cockroaches? I think a lot.