Time Blocking + No Timepieces
(technically two different techniques, but they play into each other so well)
Context: I'm a student, so all of my "work" is school stuff or fun side projects. Also, I just need to get things done my deadlines, and have no, "I'm at the place of work for X hours and need to appear active for all of them."
Time blocking is just going "I'm going to work on X for Y minutes/hours" and then doing it. If you get done early, great, you can stop. If you had a task in mind to complete, but didn't finish it in Y minutes, that's too bad, you have to stop working.
To be more flexible, I sometimes set up time blocks with conditionals. "I've got time in my schedule for a 2 hour morning block, and one after lunch. I expect X to only take 2 hours, but if it takes longer I've got the back up block." I'm cool with changing plans, but a key idea is to not end up "just working forever".
Time Blocking feels distinct from Pomodoros, which I know someone else mentioned. You can easily turn a Pomodor
No Timepieces is this: When doing work blocks, I strictly use timers instead of watching the clock. This actually extends beyond time blocks. I've gotten rid of my watch, and the clock on my computer. I try to make decisions
I do this because I noticed that it becomes much easier to loose steam if I realize that I'm 15-5 min away from the end of a time block. I also do it because I noticed that whenever I started to run up against hard problems, the very first distraction I would engage in would be to look at the clock (probably because it only required a head turn, and it doesn't feel like a distraction). When I was still habituating to No Timepieces, I would often look at my empty wrist, be surprised, and then realize "Oh, yeah, I'm encountering a hard problem and was trying to distract myself." Now a days I don't look at my wrist, but there is still a mental loop of, "I wonder what time it is?" and it helps me notice distraction.
Time blocking seems to mostly have the effect of making my commitments very concrete and clear. I'm not sitting down to "work for a while", I'm sitting down to work on X for 3 hours. In making a time block, I've already freed the time, so even if 20 minutes in I feel "Oh shit, I'm going to make very little progress" that's okay, because I've already checked that it's okay to spend 3 hours banging my head against something.
No Timepieces has given a lot of insight into how I distract myself. I've come to believe that almost all instances of me checking the time are some form of me trying to escape from the reality I'm in. "Maybe if I look at my watch, I'll see that it's time to stop working, and then I can stop!" or similarly it provides the escape hatch of, "hm, it's 2:30pm. Wasn't something happening at 4? Dinner? No, meeting Michael. Ooh, Michael's in town, I wonder what he's been working on?"