Voice

Voice alludes definition for a lot of writers. It's something we all use, but few of us have a complete grasp on.

Essentially, voice, in relation to a story, is how someone's writing sounds like. Hemingway had a different voice than Dickens, and Falkner had a different voice than Tolkien.

There are a few things that contribute to voice.

Prose
How you describe things. Do you use figurative language, or a cut-and-dry style? What voice do you use to fill in the gap for your reader when the characters aren't talking?

Dialogue
How do the characters talk? This will contribute to the overall voice of the story and individual passages as well.

Monologue
Sometimes, voice can be extended to what is going on in someone's head.

Experiment with voices. Some sound grating on people's senses when they read it, some sound so complicated people are afraid to read it, but others nearly have a poetic ring.

Try using a different voice for every POV character you use. For a book I wrote, I wrote from the protagonist's POV with a voice that was simple, straight forward, and with a limited vocabulary. For the protagonist's father I used a larger vocabulary and artistic elements to make that character "sound" more sophisticated.

For the antagonist, I decided I would try a straight forward approach, but I would try to make a lot of sentences about the same length in places. The idea was to make the reader feel abused by the antagonist every time they read that character's POV.

You can do stuff like that to. Experiment, just like you would with view point characters.