I just started my 1L a few weeks ago and from my exceptionally limited time in law school, I've come to add one to the list of gunning gunning dont's:
1) Don't be the gunner who participates every chance you get and then start off each of your blowhard comments with "I COULD BE WRONG, but I THINK...." We know you think you're coming up with something even more profound and novel than what you just said two minutes before, and then two minutes before that.. Catch my drift.
Actually, I've got one more.
2) Don't be the gunner that gets up to go to the bathroom every 15 minutes, esp. if you are in the center of the front row. At my school, this is the same person as no. 1. But some people are of the philosophy that any attention is good attention.