Some of the best non-advice about law school anywhere:

Letters of Marque: Advice to Newlings Archives

Heidi's blog has been very influential in my career as a law student.

Some of my own non-advice:
If you are returning to school after being in the work world, be prepared for the "I don't know anything!" moments. It's hard (at least it was for me) to go from a position of confidence and competence - you know your job, how to do it, etc. - to being back in "student" position - learning the ropes, how things work, who gets things done, etc. It passes, fairly quickly, but it was a few bad weeks for me.

Embrace the Uncertainty

•“I was much troubled in spirit, in my first years upon the bench, to find how trackless was the ocean on which I had embarked. I sought for certainty. I was oppressed and disheartened when I found that the quest for it was futile. I was trying to reach land, the solid land of fixed and settled rules, the paradise of a justice that would declare itself by tokens plainer and more commanding than its pale and glimmering reflections in my own vacillating mind and conscience. I found “…that the real heaven was always beyond.” As the years have gone by, I have become reconciled to the uncertainty, because I have grown to see that the process in its highest reaches is not discovery, but creation; and that the doubts and misgivings, the hopes and fears, are part of the travail of the mind, the pangs of death and the pangs of birth, in which principles that have served their day expire, and new principles are born.”

•Benjamin Cardozo, The Nature of the Judicial Process 166 (1921).