1. Every entering class has a student or two who will always raise their hand when the professor poses a question. This person is engaged in some type of Socratic-Masochistic self-flagellation. Do not be that person. If you do not know who that person is, it's you.
2. Numerous companies publish subject aids akin to "Torts for Dummies" or "The Idiots Guide to Contracts." Do not bring those to class. If you do, do not display them prominently before the professor.
3. Never lament that a decision is "unfair". Case law is about consistency rather than fairness.
4. Never discuss exam questions immediately following an exam. Never discuss grades. Discussing grades is like discussing salary: it's just bad form.
5. Don't ask too many questions.
6. Finally, there are few "answers" in law school. Yes, occasionally you'll run across actual black letter law. For the most part, law school class time is about identifying issues and applying them to an often vague law or standard. It's about advocating people and a good lawyer can argue both sides. Indeed, a good lawyer will know not only the strengths of his or her case, but the strength of the opponents case.
Keep the sand out of your weapons. Keep those actions clear. I'll see you on the beach.