How to write an outstanding nonfiction book

When you talk about nonfiction books then you need to understand and comprehend that most nonfiction books are based on thorough research and study. The writer requires amazing writing skills along with a strong grip on research skills as well. The best ghostwriters available for nonfiction writing are also known to have very good investigation skills as well because sometimes nonfiction writing requires a writer to dig up information from the past. The easiest way to write a nonfiction book is to hire a professional, in my opinion. What other ways can you think of?