When first researching how to write a fiction book, the very first thing you need to do, even before plotting, characterization, etc., is to decide what type of novel this is going to be.
Will it be a mystery, suspense/thriller, romance, action, fantasy, paranormal, historical, western, horror, science fiction, or other?
The first thing to consider is, what type of books do you normally read and in what genre? A lot of people may tell you to go where the money is, i.e. if sales of vampire books are through the roof, write a vampire book. It may sound logical, but it’s not the best idea for many reasons.
One reason is, I doubt very seriously that someone who never reads vampire books is going to be able to write a believable novel in that genre. Sure, you can go out and buy a bunch of books and read them, but why make the task so difficult?
Think of what section of the book store you normally head for when you go shopping for something new to read. If you avoid the romance section like the plaque, please don’t consider writing romantic fiction.
Bottom line is, stick with the areas you are interested in and you’ll have the easiest time writing. After all, within any genre there are many sub-genres to explore. Let’s say you do happen to be a reader of romance fiction. Your novel could be historical romance, time travel, paranormal, fantasy, and yes, even vampire.
By the same token, mystery readers can delve into thriller/mystery, science fiction, and/or horror. You must simply decide what you love to read and then write a similar book.