I try to write at least twenty-five hundred words a day on each novel, but with so many words going down, I sometimes wander off from the main plot. To get around this, I usually do several sub plots, or what's known in the publishing world as "Braiding". This allows me to wander around, and still stay on message. The trick is to fold all the sub-plots together into the Big Boy before I write that last chapter. Sub-plotting also allows you to introduce secondary characters and tidbits of information not known by the main character. These are what I call my Supporting Actors, and they help move the story along. In my series of John Locke Thrillers, I have developed a few Supporting Actors who have become Co-Stars: Uncle Fat, Gunny Reed, Hop Fung, Ralph Yee to name a few. John Locke is Da Man, but these other guys are ready to go the distance , if need be.
Try adding a couple of new unique characters to your story and see where it goes. Remember, its the Plot, always the plot.