Your first book isn't going to happen by itself. If writing a novel or non-fiction book is something you've dreamed of, the only way to make that dream a reality is by putting it into action -- day by day.
Writing time: The most important habit you can form is the daily writing habit. Even if you only write a page or two in a day, that's OK.
Writing log: Add in notes about what you wrote, how you feel about it, etc
Idea time: You will probably be thinking about your book all day, if you're engrossed in it, but it's good to make it a habit to think about your book at certain times of the day. Make that time dedicated to thinking about the book.
Capture ideas: Get a notebook or index cards, whatever works for you is fine. You need to make it a habit to write your ideas down wherever you go.
Revise: The dreaded word for many a writer, but revision is one of the most important aspects of the writing process. No one gets it right in the first draft. No one.
SHOW, Don't Tell!
Your pen is your movie camera. In a film, a director ( that's you!) doesn't have an actor go on screen to tell the audience that someone is angry. Instead, he shows the character in a scene where anger is in action.
You must challenge yourself to include everything the reader needs to know in order to understand what you want him to understand. Showing rather than telling is fairly new to writing.
Your writing itself must show as much feeling as there was in life. You don't need to tell the reader that the character was angry or scared if you depict an action that successfully shows that emotion. In fact, it takes away from the pleasure the reader has in interpreting and understanding your story for herself when you tell too much.