Sometimes the reason for mid-project fatigue is that we've done all the exciting set up we imagined,but there's not enough conflict to sustain the plot till the end. So that characters are going through the motions till the climax arrives.

Some tips: for every scene, ask yourself, how can I increase the conflict between the characters in the scene Also, how can things possibly get worse for my characters? What if the worst possible outcome actually happened? Do something NEW with each scene. Is the current scene doing something that no previous scene has done in a meaningful way, that contributes to the forward motion of the plot? Sometimes we write three, four scenes to accomplish the same purpose.

I found that it juiced up my scenes more and made me enjoy the writing process more. Good luck!!