The David Milch School Of Screenwriting
Perhaps the most important aspect of writing truly great television (and naturally something I've always been good at) is coming up with dialog that just barely resembles what each character is trying to say. When people have to work to understand what the hell is going on, they presume (correctly!) that they must be watching fine art.
I could explain this, but I'm not that good of a writer so I'll just show you through an example. Casey does not want a drink that his friend Adam is offering, but he does want to use his phone.
Adam: Want a drink?
Casey: No thanks. Mind if I use your phone, though? It's a local call. I'll make it quick.
That's horrible. Now let's punch it up by making that exchange harder to follow.
Adam: As I would offer to others who were in my house if they were here and desired it, what say you to a serving of this not-air not-earth not-fire element?
Casey: If I were to answer you in the positive I would be the embodiment of the title of that Henry Rollins Band hit from the mid-90's, and half the embodiment of the title of that Jim Carrey lawyer movie. How much of a strain on our friendship would it be if instead I asked for a rendezvous with one of your appliances which I hold close to my head and stimulate with my mouth?
Better. Not quite there yet, but better. As I learned from Deadwood, cursing is the ultimate hot sauce. It goes great with everything. Let's revise the exchange accordingly.
Adam: As I'd fucking just as soon offer it to others, I'm telling you that a glass of that liquid pleasure can pass between your cocksucking lips if you indicate in the affirmatory.
Casey: Much as I appreciate your gesture of motherfucking kindness, I'd like to communicate with another cocksucker via your telephonic voice relay device.
Now we apply the lessons learned from John From Cincinnati. Anger, insanity, mystery.
Adam: (to a chair) I'd offer it to him, but I doubt he'd... no, no. You're right. (long shot of the chair, with the camera slowly zooming in) Hey, you shitbird! Why don't you partake in this once in a lifetime offer of what some who appreciate potables might accept gladly?
Casey: (pushes Adam onto the ground and pulls out a gun) This is the cocksucking end. I wanted to ask of you a question that would possibly lead me to using your receiver and dialing pad but the device communicated with me directly from across the room vis-a-vis my left and right hemisphere. It told me... (an old scar on his cheek vanishes) These things cannot be undone unless we have fucking started them. All is Babylon.
Boom. Instant classic. That's all I have time for, as I'm off to get John From Cincinnati canceled so I can start a new show about angry, insane people who experience mysterious events as they comb a beach for buried treasure and bottle caps. Good luck out there!