When you work, if you are able to concentrate, you can do absolutely in ten minutes what would otherwise take you one hour.
If you want to gain time, learn to concentrate. It is through attention that one can do things quickly and one does them much better.
If you have a task that should take you half an hour—I don’t say if you have to write for half an hour of course—but if you have to think and your mind is floating about, if you are thinking not only of what you are doing but also of what you have done and of what you will have to do and of your other subjects, all that makes you lose thrice as much time as you need to do your task.
When you have too much to do, you must learn how to concentrate exclusively on what you are doing, with an intensity in your attention, and you can do in ten minutes what would otherwise take you one hour.
Ref: Questions and Answers 1953