Usually after 30 pages, you should go straight to the end and work backward to the middle. Films waver because you did not know where you were going. You are juggling the ending. You don't have to keep the ending, but write the last five pages, and it will feed you. Always write the dialogue first.
Description is worthless.
The camera does that. Only through dialogue do you know the scene's intention. Dialogue is everything. It doesn't have to be theatrical. It's important because it makes you think about motive.