We all hear a lot about the struggles writers can have coming up with the next plot turn, but I struggle with the opposite problem, something I call writer's rush.
Once the plot has been outlined, the main characters roughed in and I begin writing the first chapter of the narrative, I must constantly rein myself in so as not to hurry to the climax or give away plot points too early.
I'm near the end of the eighth chapter of my current work and already feeling the familiar tug to speed to the ending.
The technique I've been using to prevent my books from becoming novellas is to decide ahead of time what I want to accomplish in each segment. I bracket that goal on the page before I begin, and then paragraph by paragraph reread what I've written, comparing it to what's in the brackets. When I've covered some point, I delete it from the brackets and when the brackets are empty I am ready to move on to the next chapter. In this way, my first rough draft moves at approximately the pace I want.
Of course, goals change and those draft chapters will be revised many times before I am ready to send the work for editing, but the basic structure remains.