Why Why Writing for the Stage is Different than Writing for the Screen
1) In television or movie productions, the camera is one of the most important and influential tools that can be utilized in telling the story. On stage, each viewer only has one perspective. There are no close ups, no zooming in, no wide angles. The story must be told in action and words.
2) Related to this is the fact that on stage the story is told with the whole body. If you spend an evening watching TV, you'll notice how much time is spent on filming closeups of faces or hands. While this makes it easy to show emotion or action on screen, it just doesn't work on stage.
3) On camera, you can just pan away from a character no longer needed in a scene. On stage, you need to come up with a viable reason for that character to exit the stage, or she will end up standing there useless and distracting for the rest of the scene. It's easy to forget about a character when they're off camera, but not so easy for the audience to ignore superfluous characters on stage.
4) On stage, being "on location" in a house, climbing a mountain, or driving a car needs to happen primarily in the mind of the audience. You can't rely on the scenery to tell part of the story for you. You can film on location in the Alps, but you can't bring the Alps to the stage with you.
5) In stage plays, your audio is much more limited. You will not be able to take advantage of suspenseful background music making your lack-luster scene more exciting, and you can't count on a laugh track to make your punchlines seem funny. If you want excitement, or suspense, or humor, you're actually going to have to write it, and write it well.