A journalist friend of mine, making the leap into fiction, got some conflicting advice about "voice" in a novel. She asked me what the formula was. If only there was one! In my experience, finding a novel's narrative voice is a mysterious process of intuition, alchemy, trial and error. Every book is different, and each one demands its own storytelling voice.
My first book, The Witch From The Sea, had to be written in first-person subjective by my heroine, Tory; her perspective on the life-changing events happening to her in the novel were so much more wry and humorous than an indirect third-person narrative could ever be. The shaping of Tory's personality is what the book is about, so I really heard her telling her own story. It later evolves that she's keeping a log of her adventures, but the first-person narrator doesn't always have to be setting down her thoughts as part of the story. It's okay for the author to write from inside the character's thoughts as she reflects.
My sequel to Witch couldn't be told in the same way because too much of the plot depends on things Tory doesn't know. So I had to switch to third-person omniscient, that is, switching around between the viewpoints of different characters as the plot demands. (Alternating scenes or chapters from the heroine's viewpoint, the hero's the villain's etc.) This way, the reader gets more info about the big picture than the characters have, which creates suspense or anticipation from the reader wanting to see what happens when certain events or characters or agendas on a collision course finally do collide. This is useful when characters are in opposition to each other, but may not know it, especially in getting into the mind of the villain to get the lowdown on his or her agenda.
One of my novels (not in the Witch series) came to me in first-person present tense. ("Sun stabs through the leaded glass in the window. I can see the way they smirk at me when they think I'm not looking...") Don't ask me why, but I was physically unable to write it any other way. I needed to be inside the protagonist's head, reacting to every little stimuli the instant it happened to her. It made the whole story so much more immediate!
This is also the narrative voice I used for my new novel, Alias Hook. That's just the way he started "talking" to me in my head, looking around the Neverland and telling me what he saw and what he thought about it all. This put a few constraints on the plot; I wasn't able to wander off and follow my heroine around Neverland as much as I would have liked. But since so much of the action depends on James Hook's emotional evolution — letting go of the past, giving up the game, earning the possibility of freedom — it turned out to be the best way to tell his story. His is also a journey out of isolation, which the reader shares by being right there inside Hook's viewpoint the whole time.
First-person present tense used to be thought of as sort of weird and experimental; one story market I submitted to wouldn't even look at anything written in that format. Then for awhile, it seemed like every other novel was coming out in first-person present tense (including Philippa Gregory in one of her Boleyn family bestsellers). But these things go in and out of fashion, just like anything else, so best not to worry about the market, or what other writers are doing. If your protagonist wants to do all the yakking, let her. If you'd rather address your readers with a nudge and a wink, like Thackeray, and let them know more about what's going on than the characters know, then do that. Trust your own instincts, Grasshopper. Just start writing and the story will tell you how it wants to be told.