beside each paragraph, jot down what it DOES
ask yourself at every chapter, what is this about? why does it NEED to be here?
So what is your gift to the reader?
This is not about inserting intentionally happy-face moments to keep everyone's spirits up. That's a bit like passing out chocolate in the middle of a long hike. (And actually, I love it when people do that: it's what humour can do in the midst of tragedy; more on that later...) For the moment, let's just ensure that your story has meaning for more than just you.