My panel at Bouchercon panel was composed of Poisoned Pen writers, moderated by our editor, Barbara Peters. Fortunately she changed the topic of the Bouchercon panel from the generic "where do you get your ideas" to the topic of voice in writing. Seriously, when someone asks me that question I feel like saying I rough up homeless people and make them spit out mystery plots. Because that old adage that there are no new plots is actually true. It's been thought up before and will be thought up again and what distinguishes your rehash from someone else's rehash is your voice.
Voice is the most critical aspect of a writer's bag of tricks and the most elusive to develop. It's what makes your books written by you. As Barbara said in the panel, you can always fix a train wreck of a plot, but you can't fix a boring voice. Someone can present the most fascinating, relatively novel sets of ideas and it will still never get published if there is the absence of voice or the voice is dull and plodding.
So what is voice? To me there are two critical components to voice. First of all, it's how you, as the author, puts together words. Which sounds simple, except, this is where you put together words so that their style, pitch, rhythm, and jazz has a whole to it in your head. Sadly, this takes a whole lot of time to nail down. Like, um, years. Voice is your unique relationship (as an author) with words. The word "unique" is key here. You shouldn't sound like someone else. I find that when I write in first person my voice tends to be conversational (which is why I like first person narratives), but in third person it's a lot less snarky and more contemplative. Which, I suppose, reflects the salient differences in how different points of view work, but it's more than that. It's my brain working with two separate tools and how MY brain relates to the strengths and weaknesses inherent in those tools. Basically, it's where I finally get to the point where the disconnect between my brain and the page has been minimized to a decent degree.
Now the hard part., You've been writing for a bit, your sense of who you are as a writer is beginning to gel in your head and seemingly on the page, and then you reach the true wild card here: the readers. I liken it to us with our passports in hand. The reading train is in the station, you've bought your ticket, but you're just not sure you want to go on this journey. The first paragraphs are about wooing you to get on the train. This is my world, sit back, relax, we're going on a journey. Voice is when my writing and your internal editor are rattling along on the same train, and oh my, did you see that lion? Wow. That waterfall was something. Ha ha ha ha! Did you see those clowns? We are both seeing the same thing, laughing at the same thing, and in the case of mystery getting curious and terrified at the same thing. And there are no unscheduled stops. That is when my voice works. When we are BOTH on the same journey--orchestrated by yours truly. And that is also key. I'm the conductor, the person shoveling the coal into the engine, the flag person, and the person driving the train. Me.
What happens when my voice as an author fails? You think you're going to Africa and you find this train is bound for Hoboken. You don't finish the book. You're disappointed in the story. The characterization falls apart. The plot is mickey mouse. And yes, these are all structural things, but they do play a major part in voice, because someone with a kick-ass voice will make structural failures somewhat immaterial. Obviously, there is a point where you can only pull the wool over the readers eyes for so long, and then it becomes a case of Oz standing behind that curtain, yelling at you to ignore that man behind the green curtain, but really? Voice is the magic of a book.
Unfortunately, not everyone is going to like your voice. That's a hard thing to accept. The trick is to get most people on board that reading train. There are a few who have seen their fair share of lions, hate clowns, and are allergic to waterfalls, or (and yes, there is this), hate first-person point of view. There are a lot of readers who despise it and it's a book killer for them. I don't get that, but I have to deal with that every time I sit down and type "I."
In essence, voice is what makes the author a Pied Piper, but instead of a haunting melody on a flute, our lure is words. And the cool part about this is that every writer's song is different.