Uh Oh, No Words
They end up staring at the blank monitor, today's equivalent of a blank page, and don't know what to write next.
Egads! What do you do when you don't know what comes next? Of course, this problem arises not so much from running out of inspiration or ideas as failure to plan the story in advance. After all, a story is structured -- or it should be -- so that you know what you'll be writing tomorrow.
Sometimes even when we writers have notes or an outline or some kind of road map, we still go blank. There are days when we sit down at the computer, lift our hands to the keyboard, and nothing happens. Our minds are tabula rasa -- as clean as a wiped slate.
When You Run Out of Words
What do you do then? You write anyway. Just start writing even if it's something dull and stupid and uninspired. Start writing sentence after sentence, describing what should be happening even if you only have an inkling. Or write what the character should be doing, thinking, or feeling. If nothing else, start writing about your blank brain.
Amazingly, the very act of putting pen to paper or fingers to keyboard sparks something. Indeed, it's almost miraculous. You'll fill the page with words, and, lo and behold, many of them begin to resemble what you should be writing. Sure, it's probably yukky, stinky writing, but it's still writing.
Your brain in an act of desperation will output words. It's like turning on a water faucet. At first the spigot is hard to turn, and the water trickles out. Some of the water might look rusty and undrinkable, but if you keep turning that spigot, the flow will increase and the stream of water will become sparkling clean.
Permission to Write Badly
You know what you do with that page of bad writing? You fill the page up, and you'll probably keep going by filling another page. Then you put those pages in the stack as today's work. You see, you can fix a page of bad writing, even really bad writing, but you can't ever fix a blank page.
Nora Roberts is often quoted as saying something along those lines. I doubt if she was the first author to state that insight, and I won't be the last. It's a universal truth in the writing world. Rough draft can be edited into finished draft – no matter how awful and pedestrian the rough copy may be. Blank pages can never be edited into anything – they'll always stay blank.
Give yourself permission to write crap. Then edit the crap into sparkling prose.