Getting Things Done: The Art of Stress-Free Productivity is the book on productivity methods. In it, Allen describes a five-part system:

1. Capture things that need attention. Use a to-do list, an email inbox, a physical tray, a post-it note. Allen calls these things “baskets,” and suggests trying to keep them to as few as one needs to keep track of everything. I prefer using just one if I can help it—emails, action items, it all goes into the all-encompassing to-do list.
2. Clarify what each item means and what to do about it. Instead of “exam,” write “study for analysis exam.” Better yet, write “pick problems from Rudin to practice for analysis exam” and “schedule time to complete practice problems for analysis exam.” Make every item as clear as possible. Some things take more than one step, and should be turned into projects. In that case, make sure that they include a next action.
3. Organize each item, placing it on one or more lists. Allen suggests grouping items by context. I think this is a great idea, but I’ve never heard of it before! Grouping tasks by “do at computer” and “do in office” makes it easier to decide what things you can do in what context. This cuts down on the analysis paralysis that I often face when looking at a long to-do list.
4. Reflect on the lists. This is the much-vaunted weekly review (something that I used to do, dropped, and have since tried to pick up again). Allen suggests that one take this time to make sure that the lists are up-to-date and take this time to process stuff that you’ve fallen behind on.
5. Engage with the items. I.e. get things done.

The most important lesson for me from GTD was that every item on a to-do list should be actionable. That is, it should be an action that can be completed. Corny as it sounds, I set myself a rule to start every item on my lists with a verb: submit research proposal, fold the laundry, return library books. It feels easier for me to do things when I know exactly what I have to do.

In the rest of the book, Allen furnishes these principles with examples and more suggestions on how to implement them. I found them useful, especially the part about reminders to contact people. I usually struggle with handling text messages (strangely enough, I am more responsive to emails—they go into the to-do list, but texts do not), so these were also welcome bits of advice.

I think it’s worth a read for most students and researchers, and it can be implemented relatively quickly (Allen gives a figure of ~6 hours). There’s a very high activation energy to starting, but once I crossed that barrier everything else felt like I was following the path of least resistance. That’s the core philosophy: make it easier to do things than to procrastinate on them.