They say that in order to write great fiction you should read great novels. It follows that in order to write a great film, you should read great screenplays. So I hunted down some examples from screenplay writers I admire. Jane Espenson has written for Buffy the Vampire Slayer, A Game of Thrones, and is currently writing for Once Upon a Time. In my opinion, she wrote all of Once Upon a Time's best episodes last season, including THE best episode: "Skin Deep."
This scene did not make it into the final cut for the episode. It's not essential to the plot, though it does show that Belle (by this time) is completely unafraid of the monstrous Rumpelstiltskin.
Jane Espenson writes her actions and directions very informally. She's not writing narration. It's like she's writing a letter, speaking directly to the director, actors, cameramen, etc. More of the "Skin Deep" screenplay is available here.
For a completely different style of screenplay writing, look at this example from Lord of the Rings: The Two Towers:
Suddenly I feel just a bit sorry for Wormtongue. Yes, he's a traitor, but poor little Grìma probably didn't get enough hugs as a child. The whole screenplay is available here.
The Two Towers screenplay has four authors cited-- Fran Walsh, Philippa Boyens, Stephen Sinclair, and Peter Jackson. It's much tighter than Espenson's work. While Espenson seems to leave space for the actors to adapt her words and directions to their creative impulses, Lord of the Rings does not.
Though it's not obvious from this excerpt, the Two Towers screenplay has many, many directions regarding camera angles and cuts. Nothing is left to chance-- very different from Espenson, who seems to leave the mess about cameras to the director.
"Skin Deep" is an hour of television, trimmed to forty-odd minutes with commercial breaks. The Two Towers is a huge two-plus hour film without even an intermission. Two very different screenplays, but both brilliant.