There are certain qualifications that you must have before you actually become a law clerk.  You must be a recent graduate of a great law school where you are part of the top in the class is one requirement.  With the list of qualifications, the judges also have a say and look for certain qualities in a law clerk.

Judges need the law clerks basically to write.  As they have many things to do that include many written orders and opinions, the judges assign this job to the law clerks so that they can concentrate on other things related to the court issues and law.  Law clerks must have good judgment too. 

Since they’re going to be the eyes and ears of the judge while reading briefs and researching about the various cases, they should be people who can spot the easy and tough issues in a case.  It is a regular event then that law clerks are influential in the formation of case law in the sense that they have influence on the judge’s decisions.

Personality also fits into what judges are looking for in a law clerk.  This basically means that it should be someone who can fit in.  The judicial chambers is a small operation encompassing the judge, two permanent staff members as well as a couple other clerks.  They have to get someone who is going to keep harmony in this small but important group.  If the judge has to worry about an abrasive personality, it would be difficult to make good and informed decisions about important issues.