Take some tips from David Fryxell and the Accelerated Fundamentals of Nonfiction Writing Workshop:
Your voice as a writer is the authorial personality you assume. You put on different roles throughout your day, as the occasion demands: parent, boss, employee, friend, lover. Who are you when you're writing an article? Some writers choose to play the savvy insider, the tout; others put on the mantle of teacher, instructing readers almost as though in a classroom; still others step up on a soapbox, wagging an authorial finger as they make their points. Maybe you're a bit of a wiseguy when you write. Or perhaps you're a kindly grandparent (whatever your actual age and family status), patiently explaining things to a younger generation that could learn a lot from you if they listen.
There's no right or wrong here (though you might want to think twice before opting for the persona of "abrasive, know-it-all jerk"). Some voices are better for some assignments, and your voice, if too unusual, may simply not fit some editors' needs. But do take a moment to ponder who you are when you're writing—and what your imagined relationship is to your audience.
At an online city guide I once edited, for example, we aimed for the voice of the audience's friend—a slightly hipper, better-informed friend who knew the best new restaurants and the hottest night spots, sure, but a friend just the same. The sort of friend you wish you had, but probably don't. That voice was essential to our style. So I'd write this way in starting a restaurant review: "If you're looking for an escape from the antiquing-and-giftables bustle of downtown Stillwater, try climbing the back stairs of the Grand Garage, following the arrows—or your nose, drawn by wafts of woodsmoke—to Coupe deGrille." I assumed that you already knew the historic, weekend-getaway town of Stillwater—hey, you're my friend, and so you must be pretty with-it—and that you'd be looking for an escape from the crowds. As your trend-spotting pal, I'm happy to be able to share my latest discovery with you.
If instead I'd opted for the voice of an experienced gastronome—a food snob—I would have opened that review completely differently: "Though hardly up to the dining standards of such nearby culinary havens as the Lowell Inn, the Coupe deGrille in Stillwater nonetheless manages to achieve a passable level of American cuisine, distinguished by its smoked meats. ..." Here I'm not only putting on a different persona, but making different assumptions about my readers' needs and interests as a result.
Want to learn more about selecting the right voice? Check out the Accelerated Fundamentals of Nonfiction Writing Workshop.