So one thing I mentioned in my first post was that I've done pretty well in retaining some of the skills I learned in grad school. So, to that point - what do I think is the most important graduate school skill? Funny you should ask...
By far, the one thing you will be doing in graduate school is reading. LOTS of reading. No, really - LOTS and LOTS of reading. Like two to three books a week. And if you're a TA there's even more reading because you also have to read (or need to have read) the books your students are required to read. So let's leave it at "lots of reading" and go from there.
You could spend some money and time taking one of those speed reading classes, which might be a reasonable investment depending on how far you plan to take your academic career. But some quick guidance may help you save some money but still manage to absorb all of that information.
One thing that most people do, but don't realize, is read at the speed of talking. You read as if you're giving a lecture (well, okay - a little faster than that). But the "voice in your head" is doing the talking and it's like you're reading the book to yourself. Which, if you're doing it for pleasure, it a perfectly good pace. Or if the book is incredibly dense with material (common with technical texts but I once ran into that with a book on Prussian history - SO dense it was practically impossible to read it quickly). If, on the other hand, you've still got two books to read and a paper for your class on Thursday, "speed of leisure" isn't really a good pace. What to do?
The main thing is to recognize that you can actually absorb the content even if your inner voice is not reading it to you. You can read the content faster than your voice can keep up and still glean the information from the text. Let's give it a shot. Pick something up nearby - could be anything - and try reading it at a faster pace than you usually read at, but not too much faster. Then read it at your normal pace and see if you missed anything. Go ahead - try it. I'll wait for you to come back.
See? You picked up the pace a little bit and still managed to get the content. Now the trick for grad students is to pick up the pace a little more and a little more. Keep increasing the pace until you hit that speed that is just below your speed of comprehension. Just make sure that you're still getting the content out of the piece. When you're starting, go back occasionally and re-read it at a slower pace to make sure you're still getting all the content. I personally think the hardest part is maintaining the pace. I find that when I read for a while I tend to slow down and go back to my leisurely pace again. I have to remind myself occasionally to speed up again.
With this little bit of advice, you should be able to keep up with the rapid pace that is graduate school (or regular college even). Best of luck!