When you feel overwhelmed with your novel or story draft, I suggest that you close that file or put that stack of paper on the floor. Go to your shelf. Open a book that you love and find one of those sentences you've underlined. Here are some that I'd choose: "Her lips were dry, mean, and thin." (Alice McDermott) "Aunt Rosa, a fussy, angular, wild-eyed old lady, who had lived in a tremulous world of bad news, bankruptcies, train accidents, cancerous growths—until the Germans put her to death, together with all the people she had worried about." (Vladimir Nabokov) "Hello, my life, I said." (Grace Paley) Read the sentences out loud. Feel them in your mouth.
It's easy to forget about sentences. They don't call out for our attention like plot or character. They rarely get chapters in how-to books about fiction. But without them, there's no plot or character, no story at all. Sentences are the veins that contain the blood of the story or novel that you're trying to write. So for now, instead of going back to fix a scene or make a stretch of dialogue more interesting, I suggest that you set yourself the goal of writing a perfect sentence.
This sentence doesn't need to have anything to do with the work that you were wrestling. Maybe it's about the chip in the coffee mug on your desk. Maybe it's about a phone call with your mother last night. Or the patter of rain against the window. Maybe it's about the doubt that your story or novel has stirred in you, concretized in an image that will form if you stay long enough between capitalized letter and period for the clichés to flow away, long enough for the appearance of magical corpuscles.