I had initially began the first of a long series of books with a male main character. While listening to a writing podcast (I believe it was writing excuses), they talked about switching the sex of your main character in order to alter how you see them and to refine the core of the story.
When I did this, it completely eliminated my writers block. I have since entirely switched that main character to a female, and it has unlocked the story for me nearly entirely.
So now everytime my story starts to lag I look at how I can alter it in a fundamental way, which will so thoroughly change the way I see the story. In order to hopefully unlock the next scene which seems to allude me.