What makes a good idea?

What makes a good film? Same thing. If you can imagine your idea on the big screen then its probably going to make a good film. It needs to be visual (so no introspective characters) and like any good story has to have a beginning, middle and an end. You have to fully exploit your idea, so if you've got a great beginning, make something else happen in the middle, then give it a good resolution. The story and the characters have to go somewhere. The audience has to care what happens to the characters. We have to empathize with them.

Boil a film down to its basics and what usually happens is this : A character gets involved in some sort of situation, which gives them an aim. They spend most of the movie struggling to achieve this aim, just before the end it becomes 'make-or-break' time and either they work out how to achieve the aim, or the aim gets more complicated, usually both. Then the story wraps itself up as the character sorts the problem out. Roll credits.