I was just in a on-line discussion with a group of authors. One of them had lost his way in the novel he was writing, and a number of us, knowing the "lost realm" well, suggested the tools we used to help us get back on track.
I recommended Blake Snyder's Save the Cat. I'm using his system now to help me see the shape of the two YA's I'm writing, and I used it last year, as well, to find my way out of the maze of The Next Novel. His book is irreverent, far-from-literary, but it gives you plot basics with a good dash of humour. Plus, it's short and to the point.
Both these books are written for scriptwriters. My own conviction is that scriptwriters are story-specialists, and that novelists can learn a great deal from them.