The best way to learn how to write a book is to read and write. Seriously. The write part is easy (hahaha—at least in theory). Write. As much as you can—early in the morning, or at night, or at lunch, or write every day at a specific time, or, or, or…(for ideas on time to write, here are some ideas in Make Time to Write and Find Time to Write). You get the idea.
Now for the reading part. If you are a writer, you are probably a voracious reader. Read, read, read everything you can, especially in the genre you want to write. Reading other’s work will help you study story structure and analyze what works and what doesn’t so you can apply concepts of writing that resonate with you to your own writing. How to do this? Read first as a reader to enjoy the book, then go beyond the “magic” and take a look behind the curtain to discover how the writer enthralled you. Get that other part of your brain working—not the imagination part, but the analytical part. Read as a writer. Deconstruct your favorite novels.
Novel deconstruction isn’t a book report where you just tell what happened in the book. This is a method of digging beneath the surface of the book to see what makes it a can’t-put-it-down read. This can be an eye-opening experience. Give it a try!
via Ten Steps to Deconstructing a Novel (or How to Learn from Great Authors) | How To Write Shop.
Geoff Brown -Writer 
My biggest complaint is having a great idea for a novel, and then finally getting around to reading something I’ve had in my TBR pile only to findthat some other bastard has already published my idea (10 years earlier) and missed the best bits out.
I read everything, fiction, non-fiction, poetry and prose. It’s good for the brain. I write when ever I can – even when I’m not putting words on screen (or paper) I’m thinking through an idea, talking to characters, hearing them exchange dialogue with other characters and analysing how they think, dress and move.
Fortunately I do not appear to be alone in this. Reading Robert R. McCammon’s “Swan Song” and wondering who plagarised who – Stephen King (in The Stand) or McCammon in Swan Song. The only difference is the cause of humanity’s demise. The rest reads like they were given the same story seed and asked to include the same characters.