Before you begin to write your novel, you must dream up a winning story idea. Once in a while, writers pull ideas for their novels out of thin air. Rather than waiting for the fiction-writing muse to strike, give her a nudge.
To start the brainstorming process, think about the types of novels you enjoy the most. When you go to the bookstore, do you gravitate to the mystery section, the sci-fi section, adventure, romance, historical saga, horror, westerns, fantasy, or general fiction? Most often fiction writers have the easiest time writing in the genre they read and enjoy.
Once you narrow down a category or two, pick three or four novels by your favorite fiction authors of that genre. Take the time to read them slowly -- cover-to-cover. As you read, dissect them ... feel the rhythm of the story, note the balance of narration and dialogue, internalize the pacing. Can you find some commonalities among the novels in your genre? If so, make note of them for future use.
Reading several novels in this analytical way should clear a path for your book idea. Keep a notepad handy and jot down all the ideas (no mater how foolish) that come to mind. Put the list aside and keep reading. If you let those ideas for ferment for a while, one or more will eventually rise up to claim your interest to an extent that you won't be able to leave it alone.
That's your start. Fiction writers tell me, and I know from personal experience, that once an idea takes hold, it'll start to grow on its own. Don't rush this process in preparing to write your novel. Waiting for the right idea will make the writing process so much easier.