Part of the problem in talking about voice is that voice is interwoven with a writer’s personal style. Several points on the list need to be taken loosely, since what is effective can cover a broad range.
☐ Paragraph and sentence lengths are varied in accordance with pace.
Monotonous sentence structures are a hallmark of novice writing. When I see sentences that are all pretty much the same length and meter and structure, I can presume the writer has just not practiced the craft for very long. Hemingway is known for his terse sentences, but he could pull off a lengthy sentence when the scene called for it. Variety of sentence structure will improve your story’s flow. Whether you prefer short sentences like Hemingway’s or long Faulknerian rambles is a matter of personal style, but either way, occasionally incorporate a dash of the other to keep readers engaged.
One of the most common sentence length issues I see is a string of lengthy sentences in an action scene. Short sentences speed things up. Long ones slow the pace. To keep an action scene moving, cut quickly. Then, when the hero catches a breather, you can pull out a long compound sentence and give him a moment to survey the scene before he leaps back into the fray. In a fast-paced sequence, any time you’ve joined two independent clauses with a comma and a conjunction, try changing the commas to periods and deleting the conjunctions. See if it doesn’t speed things up.
☐ The voice avoids being too distant, intimate, offensive, or stilted.
How distant is “too distant” depends on your style, your genre, your characters, and your story. Not to mention your target audience. It’s hard to get “too intimate,” since readers love to be deeply embedded with the character. But some books aimed at the Christian market have been criticized for having gone too deeply into the psyche of a sexually aroused character. And if you’re writing from the viewpoint of a psychopathic child molester, you probably want to avoid getting too close.
An omniscient POV story with an epic span and a cast of thousands will by necessity be distant, but an emotional family drama told in deep POV with a small cast in a cozy setting calls for a more intimate voice.
Even offensiveness is closely tied to audience. It takes a deft hand to pull off an offensive character—Archie Bunker, for example—but it can be done if you know your audience will go for it. But you never know how tetchy some people can get. Witness the brouhaha over Neil deGrasse Tyson’s December 25 tweets. If your critique partners or beta readers warn you that something you’ve written could be taken the wrong way, pay close attention.
How stilted is “too stilted” will also depend on your POV. An omniscient narrator could be stilted, but need not be. If the primary POV character is a stilted person, then the narrative voice could be a bit stilted to show that. But if your POV character is laid-back and slangy, the narrative should be, too.