As a PhD student, you probably think a lot about how to manage your time. But one aspect that's often overlooked is how you manage your effort.
You might think that it's all about working harder; putting in more effort to get more done. But there's a limit to how much you can achieve this way.
Most of the time, you shouldn't be working as hard as you possibly can. Instead, you should aim for about 60% effort; being focused on a goal, but relaxed.
This is not only more sustainable, but often more effective too. By relaxing, not rushing and not worrying too much about the end result, you're far more likely to be able to see solutions to the problems you face.
If working harder isn't working, maybe it's time to relax a bit.