Pomodoro is my secret weapon when the push comes to shove. I pulled out a couple of hard things in "deemed impossible" amount of time with it.

You can tune Pomodoro's work lengths. 25 minute is the sweet spot for me, but you can go 20 or 30 depending on how your mind works and endures.

Also, don't forget to take your long, 15 minute breaks after every 4th pomodoro.