With the recent discussion about advice to aspiring federal law clerks, I thought I might drop my quick thoughts on what federal judges may be looking for when they hire clerks (having hired law clerks as a federal district court judge for the last five years).
Judges are basically hiring law clerks to do one thing: write. Judges assign law clerks to produce written orders and opinions and the like, so applicants would be well advised to show they chave the skills to carry out such assignments. Thus, the "writing sample" is one of the most important things in the application. A published law review note is one way to establish writing skills. But notes often have often undergone so much editing that they have an "institutional" feel to them and leave the reader wondering how much writing was done by the author and how much was done by the editorial staff. An unedited draft note or an unedited law firm memo may help put these concerns to one side.
Judges also looking for someone with good judgment. Law clerks are going to be the eyes and ears of the judge in reading briefs and researching cases. Someone who can spot the tough issue (or the easy issue, for that matter) is obviously much to be desired.
Judges are finally looking for someone who will fit in well for a year. A judicial chambers is a small operation, typically comprising the judge, one or two permanent staff, and a couple of clerks. Throw an abrasive person into that mix and you have a recipe for a bad year. Judges (no less than other employers) are very risk adverse and want to make sure that they are getting someone who won't be a monkey wrench in the machinery.
In light of all this, I don't think taking particular law school courses is valuable. Of course, an aspiring clerk should avoid taking a bunch of Mickey Mouse "Law & ...." courses, but instead should get courses of real substance. But beyond that, there is only one course I would recommend for aspiring federal clerks: Federal Jurisdiction. Federal jurisdiction is very complex and tough to pick up on the fly. This is the one course on a resume that usually caught my eye. (I suspect that for state Supreme Court Justices one class would be attractive: state constitutional law, an extremely important yet underappreciated subject.)
I would also strongly recommend getting to know one or two professors well. Because judges don't want to hire a dud (or, worse, a problem), they tend to rely on people they know well. For example, I tended to hire almost exclusively from my home state schools (Utah and BYU) or my alma mater (Stanford) because I knew the professors at these schools wouldn't let me down by recommending a problematic applicant. We were in a long-term relationship, which meant they would candidly tell me when someone who was good "on paper" was not going to fit in well.
Ideology was never a big factor for me. Perhaps it is different in the courts of appeals, but 99% of district court work just isn't political. As a result, I asked only one question along these lines: Would you have any problem working for a reputedly "conservative" judge? Invariably the answer was "no", and that was good enough for me.
Update: As a "take-home exercise" for aspiring law clerks, I have intentionally left several typographical and grammatical errors in this post so that they can practice their editting, er, editing skills and show that they are not risk adverse, er, averse to hard work. :)