So Long, and Thanks for the Ph.D.! by Ronald T. Azuma,
Grad School Survival by Alice Domurat Drager, and
How to be a Good Graduate Student by Marie desJardins.
These are all excellent resources for incoming (or even second-year or advanced) graduate students, especially those who are pursuing doctorates.
The piece of advice that I found to be the most important was present in all three pieces: be certain that you want this. Be passionate about it. But if you don't believe me, listen to them:
"The most basic question every Ph.D. student must know the answer to is: 'Why the hell am I doing this?'...If you do not have an acceptable answer to this question, then don't get a Ph.D. I repeat: if you do not have a rock-solid reason for getting the Ph.D., then it is better that you leave with a Master's." - Ronald T. AzumaConvinced? I hope so. Because from where I sit, this is the most fundamental piece of advice that any of us could take to heart. And I don't think it takes too many weeks of graduate school to realize its merit!
"Finally, if you wake up every day hating what you’re doing, get out of it now. Don’t become one of those tragic people who finds herself or himself years into an academic life struggling every day to make a career of something s/he hates. Academia is a lifestyle choice. If you hate that life in graduate school, you’re probably going to hate it long term." - Alice Domurat Dreger
"First, why go to graduate school at all? The usual reasons given are that a Ph.D. is required or preferred for some jobs, especially research and academic positions; that it gives you a chance to learn a great deal about a specific area; and that it provides an opportunity to develop ideas and perform original research. Wanting to delay your job hunt is probably not a good enough reason. Graduate school is a lot of work and requires strong motivation and focus. You have to really want to be there to make it through." - Marie desJardins
As far as what I personally find most helpful: as graduate students, we all have a LOT of work, and often are managing quite a few projects at once, especially when we have classes AND research to do. Frequently, the projects are long-term and formidable. That's what I'm facing right now, and even though most of what I have to do isn't due until close to the end of the semester, I set daily goals for myself so that, in smaller pieces, the work gets done. As I mentioned in class, I find that my best time to work is in the morning. I don't particularly relish getting up early, but I think much more clearly and can produce higher-quality work during the morning than even the afternoon (and definitely at night). I try to front-load my days so that by the time evening is nigh, I either stop working or only work on tasks that don't require a heavy cognitive load.
An item of interest: I was most surprised and intrigued by Dr. Dreger's warning against hypochondria. Apparently, based upon her own observations as the wife of an internist, it seems a lot of the "brainiest" people notice their bodies acting up. Aside from an obvious lack of sleep, I haven't really noticed these sorts of issues among my colleagues. Anyone want to jump in and disagree?