The most memorable novels, short stories and other narrative forms are unique because of the way a writer's voice is composed on the page. The key elements to remember when establishing your own narrative voice are diction, which creates the tone and mood with your language choice, style -- which includes sentence structure, rhythm, and form -- personal examples and experience, and first- versus third-person point-of-view.
Diction: Tone and Mood
Diction is the author's choice of words for description, narrative emotion and character speech. The way an author uses language and the specific words he uses make his characters and narration memorable. In writing, particularly fiction writing, tone is the attitude of the narrator in first- or third-person voice, while mood is the overall feeling the reader gets from the story. Description, narrative action and dialog help to create mood, while tone is conveyed through the narrator's outlook on events.
Narrative style develops as a writer experiments with sentence structure, the rhythm and pacing of his language, and the overall form his storytelling takes. For example, if your prose form has short paragraphs and sentences, minimal description, and is narrated in quick, choppy sections, then your voice has more directness and more of a sense of urgency to it. Your voice is affected by your stylistic decisions because the way you use language is how you communicate to your reader.
George Orwell once explained that "the more one is conscious of one's political bias, the more chance one has of acting politically," which suggests that voice is also based on a personal belief system and life experiences. All writers get content from their life experiences, regardless of whether or not they write fiction or nonfiction. This personal experience helps to compose voice because it makes writers' plots, characters, and themes distinguishable to readers. Orwell, for example, wrote about politics and conspiracy theories, which is what his voice became known for. Your own narrative voice is dependent upon the sociocultural experiences and knowledge you have gained in your life.
Point of View
While a writer's voice rarely alters from story to story, his narrative voice will indeed change, depending on the type of character that tells the story. A first-person narrator is automatically more connected to the reader since he speaks directly to the reader about himself, whereas a third-person narrator can often feel more detached to readers because he interprets the characters for the reader. However, third-person narrators still strive to be objective, so that readers can draw their own conclusions about a story's characters. Making a decision about point of view should be based on how intimate you want your readers to be with your characters and whether your main character would make a reliable and honest first-person narrator.