I'm a long time fan of writer and playwright David Mamet. His films stand out for their stylized, pithy dialog and intricate plot twists. Glengarry Glen Ross (winner of the Pulitzer prize) is a classic. If you've never seen House of Games, Things Change, Heist, Wag the Dog, Oleanna, or The Spanish Prisoner, you should rent their DVDs.
Mamet was interviewed recently by Robert Hughes in the WSJ. Several of his answers dealt with his own creative process.
WSJ: How hard is plot for you?
Mamet: I once worked for a summer laying sod. This is the only thing I've ever done that was harder than that. You've got to get over your own cleverness. You have to become extraordinary analytical, and throw out all the stuff you love to get there. Sometimes it doesn't make sense. You stare at that sheet of paper for years and know there's something hiding in there.
WSJ: When you begin writing, do you have an idea where it's going to go?
Mamet: You've got to get in there and start mucking around. After a while the material is going to correct you. You have to listen to it, and extract the play that is hiding in your subconscious. If it can't trick you, it can't trick the audience. You have to follow your unconscious thoughts so that eventually you're encased in a structure that, as Aristotle says, is surprising and inevitable.
WSJ: Are you ruthless with your own rewriting?
Mamet: Oh yes. I don't care. I do it for a living. If something doesn't work, I'm going to throw it out. What pleasure is there in saying I'm right and the audience is wrong?
I'm no Mamet. But I will say that my writing experience (books and other products) is similar to his in this regard. Almost every time I've been stuck, it's usually because I've been in love with a particular idea, theme, metaphor, or quote. Only when I've "thrown out the stuff I love" (as Mamet would put it) do things begin to flow in a constructive way.
What can you "beloved ideas" can you throw away? What might that open up?