From The Creative Habit by Twyla Tharp:
The only bad thing about having a good creative day is that it ends, and there’s no guarantee we can repeat it tomorrow. One good day does not necessarily beget another. But there are ways to increase the chances of successive successes.
Ernest Hemingway had the nifty trick of always calling it a day at a point when he knew what came next. He built himself a bridge to the next day. I cannot think of a better creative organizational tool. The Hemingway bridge is how you extend a mini-groove.
I try to do a variation of this bridge. I always quit for the day before everyone’s totally exhausted. I stop when there’s still some energy left in the room and I know where we would have gone if we hadn’t stopped. Knowing what comes next is like crocheting: The end of one day knits into the next, and you wind up with a garment that is flexible but strong.
A savvy stand-up comedian always knows to leave the audience begging for more. You should do the same with your work. Don’t drive yourself to the point of being totally spent. Try to stop while you have a few drops left in the tank, and use that fuel to build a bridge to the next day.