One key to successfully writing nonfiction is to provide timely, accurate and, in some cases, detailed information on your topic, written in a reader-friendly format. For the latter point, find your own writers voice (what and how you will deliver your message) by deciding things, such as, (1) Your purpose for choosing the topic and writing about it, (2) What you want to say, (3) How you want to present it visually and in writing, and (4) Who your readers will be.
Once you have found your voice, you will need to decide what “person” you will write in grammatically. I like to use second person and talk to my readers (as in this paragraph). Some people choose third person (e.g. Many nonfiction authors choose to write in a style that is less personal). It is really an individual preference and can change depending on topic and desired outcome for the work.