With each passing day of my design education it seems that I arrive at more questions than answers. A lot of what you get out of school is asking questions, more importantly the right kinds of questions. However sometimes good ol' advice is more beneficial and rewarding then asking questions.
On the Core77 Boards there is a thread titled "If I Knew Then What I Know Now." Before I came to school I glanced at it and really paid no attention to it. Now that I'm in my sophomore year this thread has become somewhat of a credo for me, a manifesto if you will. The thread encapsulates the design education of multiple members each with their own words of wisdom. The advice is comprehensive, covering studio life, what skills employers are looking for, and even the rule for how young grad students can date.
I urge anyone who is currently in school or applying to read this thread thoroughly. It will give you a sense of purpose and instill a level of motivation that you didn't know you had in you. Read the thread in its entirety, even reading the debates between people who don't agree on the same piece of advice (take your own stand on it). Try not to listen to one person's advice but a diverse group of people.
Students working in MIT's Design Studio
The thread has become somewhat static lately so if other talented and experienced designers would like to share their advice please post!