Are you copying someone else's writing voice? Writing voice is unique. Every writer has his own writing voice. To test if your writing voice is unique,simply read it aloud and you will know if you compare it by reading aloud adifferent text. If you copy someone else's voice, your story or work will not be as good as it will be if you used your very own writing voice. It takes time to develop but it's worth it. Just practise writing as you like it; don't try to copy famous authors' writing voice. (More resources about writing voice: here and here. Have trouble finding your writing voice? Then read this post).