For years, I've been happy if I wrote 3K words a week. How do you go from that to writing 10-12K?
The trick is kind of the same trick. For the run, all you need to do is run 2.5 miles away from your house. Then you are forced to traverse that 2.5 back, and the fastest way to do it is to run.
Same with word count. If you have a deadline, you don't have too many choices.
Samuel Johnson once said that the prospect of hanging concentrates the mind wonderfully.