Not falling asleep by your usual bedtime is a bit like missing your bus home when it's really late at night. All you can do is wait until you're tired again. By that time, opportunities for sleep (much like the buses) only come about an hour or so apart. That is, if they're still running at all. So you just have to lie there and wait until the feeling takes you again. Perhaps you try to busy your mind, tricking it into thinking it's more tired than it really is: "Draw some feathers," you command. "Now open Photoshop." And you do. And still, you wait. Because you already missed your bus.