Read. Read. Read. Just don't read one type of book. Read different books by various authors so that you develop different styles.
It's just different discipline, just doing the voice over. I guess I've done about 5 or 6 audio books in the past and I do the animated voice for a show called Fatherhood on Nickelodeon.
I usually give a book 40 pages. If it doesn't grab me by then, adios. With young adult books, you can usually tell by Page 4 if it's worth the time. The author establishes the conflict early, sometimes in the first sentence. The themes of hope, family, friendship and overcoming hardship appeal to most everyone.
The true treasure lies within. It is the underlying theme of the songs we sing, the shows we watch and the books we read. It is woven into the Psalms of the Bible, the ballads of the Beatles and practically every Bollywood film ever made. What is that treasure? Love. Love is the nature of the Divine.
I basically only read books that are over 2,000 years old.