I haven't blogged for bunch here, but I thought I would just make a list of advice I thought of as I've been in graduate school a while and am starting at a new school. This advice isn't necessarily unique, but hopefully it will help people anyway.
It doesn't make sense to apply to a few top graduate schools, it makes much more sense to apply to many top graduate schools. This rational should make sense; if your ultimate goal is to go to a top program, apply to all of the top programs for your best chance. Too many times I see people who target midteir schools and throw in their random MIT/Harvard ect. You might get lucky, but chances are if you are only applying to 1 or 2 top 20 schools, you wont get into a top 20 school. Another way to phrase this is apply to the schools you most want to go to.
If there is severe weakness on your application, such as bad GPA or GRE, you should be embarrassed about it and act like it. Being embarrassed about it gives off the idea that you are used to being excellent at everything, and this is just a setback that you wish you didn't have. The wrong attitude is "Grades don't matter" or "I just don't test well". Perhaps this is true, but you are trying to sell your self to graduate schools.
Be honest about how general your research interests are, being super specific does more damage good for the most part! A PhD is a research degree designed to teach you how to solve open problems. The things that matter most are department and advisor, but the research project can be enjoyable as long as it fits in some general research interest. I'm not telling you to research Russian Lit if you are only interested in American Lit, but perhaps the period of American Lit you study can be more flexible. In graduate school you are exposed to tons of new ideas, the development of your research should be affected by them. Apply to work with strong advisors in strong departments and worry about the last 10-20% of research fit later, you will probably find that it doesn't matter anyway!
During interviews and visiting weekends, be yourself. Because the serious "I need to get into graduate school" version of yourself is probably a lot less likable than your normal self. And people want to accept people they like. Think of it like a first date.
Write early and often, because eventually you will hate your thesis/dissertation. Everyone I have talked to (including myself, yes, I talk to myself) goes through a period where they hate their research. This period usually comes when you are in the final stages of writing your thesis/dissertation. For me, it came after I finished my MSc Thesis but needed to do revisions after the defense. My committee handing it back to me with corrections and annotations made me want to throw up. I think this stemmed from the fact that I wrote ~50% of it in a 4 week period, when most of it could have been finished a lot earlier!
Help other graduate students who are struggling in the classes of your specialty. If you are taking a class with your advisor or in your subfield, and people are taking that class for breadth requirement, help them when they need it! This will make it much more likely that they will help you when you are fulfilling your breadth requirement in their subfield !
Make friends outside your department. Because department politics get old.
Be 100% honest with your advisor. It makes it much harder for them to give you good advice if you aren't honest. If they say, hey can you write that program for me and have it to me by Friday, but you are swamped, its ok to say "well I have a lot to do this week, perhaps I can get it to you on monday or tuesday next week ?"
Don't be afraid of Bs. If you are getting all Bs, there is probably a problem. If you are getting all As, there is probably a problem.
Don't skip happy hour because you have a lot of work. This is pretty self explanatory. You can always go for an hour then head back to the lab. Just stick to your limits, but always try to do something social every day, even if it is just chatting over a single beer for 30 minutes to an hour with someone.
Learn how to fail gracefully. Because most of the time you will fail, until you graduate, when you succeed. Learning from these failures is the most important thing when trying to get through a graduate degree.
Anyway... thats all I can think of.