The ABA Litigation Section's May 2008 installment of "Tips from the Trenches" is by Seventh Circuit Judge Richard A. Posner, "Convincing a Federal Court of Appeals." A tidbit:
In a case that is not controlled by precedent, the task of the advocate is to convince the court that the position for which he or she is contending is the more reasonable one in light of all relevant circumstances, which include but are not exhausted by the case law, the statutory text, and the other conventional materials of legal decision making. I say “reasonable” rather than “correct” to give due recognition to the ineliminable element of discretion in the decision of a case that is not ruled by precedent or other conventional sources of law.
The most effective method of arguing such a case is to identify the purpose behind the relevant legal principle and then show how that purpose would be furthered by a decision in favor of the advocate’s position. ....
Let me close this very brief discussion with a miscellany of do’s and don’ts of oral argument:
1. Try to dress well for oral argument. Make the judges think that you are a serious person who takes the court seriously.
It's quite interesting that Judge Posner considers it necessary to offer lawyers that last bit of advice. [Via How Appealing]