The most important piece of advice?

Here is a great post, over on ProfHacker, about advice to new grad students: An open letter to new graduate students, by Brian Croxall. While I agree with most of these topics with varying degrees, they did not include the most important piece of advise, probably because it is so obvious: ask questions. Our role as advisors is to advise, but we can only do this if we get questions. Come in my office, send me an email, skype, whatever. And if I do not answer, which will happen, as some will attest to quite vocally, resend the email.