Unlike firms, which typically elect to be governed by offer-and-acceptance guidelines of the National Association for Law Placement with regard to the on-campus interviewing process, judges are their own masters. Indeed, perhaps the most difficult thing for students to accept about the clerkship process is the fact that you do not have the freedom to gather multiple clerkship offers and then decide which one to accept. Instead, many judges are of the view that it is impermissible to turn down one judge in the hope that another will give you an offer, or to "leverage" one offer in order to obtain one that you prefer. Unfortunately, a twenty-four hour consideration is probably the best you can hope for.
So what do you do? There are different possible responses. One response is to remember that there are few former clerks who did not love their clerkships, and that the differences among judges usually is not great enough for you to torture yourself about not having gotten the particular clerkship you now think you would have preferred. For most students, we heartily endorse this view.
If you are a student for whom the prestige differences among clerkships are particularly salient, the only viable solution is to think strategically before you begin to interview. You may want to send your applications in waves; give your "first choice" judges some time to review your application before you apply to your "second-choice" judges. Another strategy is to try to interview with your first-choice judges before you interview with others. It is very important to keep in mind, however, that strategic choices like these can lead to not getting a clerkship at all. Your second-choice judges are someone else's first-choice judges; by the time your second wave of applications reaches the respective chambers, you may have lost the race. This is particularly true if interviewing and hiring is condensed into a short time period, as it is likely to be. In short, be strategic at your own risk. And the riskier the strategy you intend to follow, the more advice you should seek before committing yourself to it.
In the end, the best practice is not to apply to any judge from whom you would not immediately accept an offer!