Scott, last year, I took an awesome screenwriting course at NYU. The teacher, who also happens to be a co-writer on one of last year's Black List scripts, had us read a section of the book "Audition" by Michael Shurtleff. Specifically, we read the section on the
12 Guideposts, which is intended to help actors understand 12 important components to a scene. It's amazing how well these tips map to the essentials in writing a good scene. I have the list posted on my PC and refer to it over and over before tackling a tough scene.