[From the archives at RSL.]
It is said that Milo of Croton, the six-time Olympic wrestling champion, maintained his strength between the Olympiads by lifting a calf onto his shoulders every day from its birth. After four years, then, he was lifting an ox, and, so the story goes, he carried this ox on his shoulders right into the stadium, where he killed it with his bare hands, cooked it, and ate it.
You know where I'm going with this. How like a PhD student was Milo the Crotonian! For three years (give or take) you grow with your task until the day comes to defend your thesis. You throw the dissertation from your shoulders to the ground, deftly slaughtering it before the amazed eyes of your committee. Then you cook it, of course, and consume it with the utmost relish.
What intellectual exercise can serve as a fitting analogue? Well, from the first day of your doctoral studies, write down something you know (I mean really know) about your topic. Do that again on the second day and then again on the third. Do it every day for a thousand days (three years or so) and you will then know enough about your topic to justify your degree. You will also have written, more or less, your thesis.
Give your research a daily workout (an e-labor-ation) in writing from the very beginning. By this means you will arrive at an articulate body of knowledge just as surely as Milo achieved his Olympian strength.