Some modest advice for graduate students just got passed around our department (by a professor no less). I think Stearns has done an admirable job in being truthful about the realities of graduate school in the sciences. Much of what he states I've had to learn from experience. But I'd like to add a few points:
Good science takes time.
Either spend 60+ hour weeks for a few years or 40 hour weeks for a lot of years (or unfortunately, 60+ hour weeks for a lot of years). Plan on experiments, field work, and writing to take much longer than you anticipated. Plan on pursuing a lot of dead ends before you make something work. I once read that you should budget one third of your time to planning a field campaign. For example, if you anticipate 2 months of field work, plan on a month getting equipment ready, devising sampling strategies, making travel arrangements, looking at maps.... Read relevant journal articles more than once - you will always miss something the first time. Go through multiple revisions with the other authors of a paper before submitting it. Expect that the time from writing first (nearly-complete) draft of your first paper to submitting your first paper to be several months longer than you anticipated.
Make friends of your fellow grad students.
Your fellow grad student friends are the only ones who will understand what you are going through. Faculty members have either forgotten or repainted their memories with rose-colored glasses. Family members will wonder why you are "still in school" and why you don't " just get a real job." Friends from high school and college will get good paying jobs, marry, and have babies while you are "still in school."
Your grad student colleagues will be there to share late night pizzas and mid-afternoon coffees. They will listen to you vent about committee deadlines, broken lab equipment, and stupid classes, as long as you take your turn listening. More importantly for your career, they are often willing to offer occasional field assistance, proofreadering, constructive criticism, and collaboration. Again, you must take your turn helping, but in the end a few hours spent prepping someone else's samples or ripping apart a paper may net you a life-long collaborator. And don't limit yourself to only those in your lab group, look for people in complementary fields. They'll bring a different set of expertise and perspective to your work.
Don't forget the big picture.
In the throes of thesis work, it is all too easy to get lost in the details of your specific experiment, theory, or field site. Force yourself to step back every once in a while and put your work in context. How does it advance our understanding of the way the world works? How does it solve a problem for society? How is it not limited to a specific, unique place or species? Try to write the introduction to a planned paper. If you are left feeling like it is only a minor contribution not deserving of your field's attention, then you've probably forgotten the big picture.
I'll add more as I get a chance. I'm going home to bake cookies and play with the dog.