Voice is style, plus theme, plus personal observations, plus passion, plus belief, plus desire. Voice is bleeding onto the page, and it can be a powerful, frightening, naked experience. But your voice is your future in writing. And here is how you develop it. You cannot be a successful writer if you don't read.
All writers read, and all good writers read a lot.
Read fiction, read nonfiction, read in the genre you love, read outside of it. Read WAY outside of it. The more you read, the more you will acquire a visceral instinct about what works for you, and an equally compelling instinct for what doesn't. You'll discover how stories are put together, get a feel for how good novels are paced and plotted and how bad ones fall apart, and you'll start developing a hunger to write specific stories, because you'll come across areas of fiction where nobody is writing the kind of books you want to read. Reading is magic.