This article at the Writers Store by William M. Akers gives great advice on rewriting your script, but most of it can be applied to your novel as well.
This article focuses on three things - story, dialogue, and scene description.
Screenplays focus on structure and story, whereas novels can and often do wander all over the place, and sometimes aren't very story driven. But if you want to tell a story, structure is your friend, even in a novel.
Yes, dialogue in a screenplay needs to be lean. But you don't want the characters in your novel repeating themselves, do you? All the points here can help make your novel's dialogue sing. I'd add my own tip, taken from movie director Howard Hawks, who called his dialogue, three cushion dialogue. It's a term from pool, where you bounce the ball off of three cushions before sinking it. Hawks never wanted dialogue that went straight to the point. He thought it should bounce around its meaning, getting to the point obliquely. Don't have your character say "I love you." Have a character who is a coffee snob say to their beloved: "You make good coffee." You get the idea.
Sure, scene description in your novel doesn't have to be as tightly focused and written as in a screenplay. But shorter is often better, and tightening it can make you get to the heart of your description in a more powerful way.