on Writing Forward:
Writing a novel is no small task. In fact, it’s a momentous task. Some writers spend years eking out a first draft, followed by years of revisions. And that’s before they even think about the grueling publishing process.
In other words, you’re going to spend a lot of time with your novel. So you better love it. No, wait — loving it is not enough. You have to be in love with it. You have to be committed to it. Obsessed with it.
It’s normal to lose interest when you’re on your tenth revision, but if you’re losing interest in your plot or characters while writing your first or second draft, the problem might not be you or your novel. The problem might be that you tried to commit to something you didn’t love. That’s never a good idea.
For many writers, the trick to sticking with a novel is actually quite simple: find an idea that grips you.