Try writing in the morning for a week and see if the time of day makes a difference in your writing output. If you're averaging 1,000 words per hour session at night and 1,500 words per hour session in the morning, it might be worth considering getting up a little earlier every day to take advantage of a more ideal time to write.

Try writing in two thirty-minute bursts rather than one full hour and see if smaller periods of more intense focus make a difference. If you're averaging 1,000 words per hour session but, say, 750 words per half-hour session, it might be worth considering breaking up your writing time into smaller chunks separated by a break for a walk, a meal, a nap, etc.

Try changing the order of activities in your life. If you get up early enough to write and work out in the mornings, compare writing output of working out first and then writing with writing first and then working out. If working out before you write gets the blood pumping, wakes you up, and gives you more energy to write an additional 500 words in the same amount of time, it's worth making that change to your schedule.

Try different environmental factors: with or without music, on the couch or at a desk, at home or in a coffee shop, etc. Again, if you can squeeze out another 100 words by using headphones to drown out ambient sound, and another 100 words by sitting at a desk rather than reclining on the couch, and another 50 words by keeping a bottle of water near you rather than running to the kitchen even twenty minutes, it's worth changing those aspects of your process to maximize your benefits.