Okay, I've just submitted to the final round of the NYC Midnight Short Story Challenge. I'm not happy with the edit of my submission (an extra hour to proof read and implement minor changes would have been ideal). But it's been a great experience I've learnt that I can write short fiction. I feel I understand the medium and what it is good at doing. BUT I realise that I don't understand screenplays the same way. So, in two sentences or less, explain what writing an effective screenplay is al about.