Here are a few things to think about.
First, write the way you talk. Be as natural as possible—but be grammatically correct. People need to be able to hear you on the page. The greatest compliment I receive from readers who know me is, "I could hear your voice as I read your book."
That's the affirmation that helps me know I'm succeeding.
Second, remind yourself that your voice is unique, And every true voice is unique. Every voice—your voice—has something valuable to say, and it becomes more effective and worthwhile when spoken in your own words.
Third, as you accept your voice, it begins to sound authentic and true. From there you have the freedom to expand and grow.
Think of finding your voice as a sacred quest. Respect your search.
Fourth, consider your voice as a gift from God, which it is.
And no one can write the way I do except me.