Before publicizing your opening for interns, spend some real time thinking about what you want your organization to get out of this arrangement and what you want the interns to learn. You might even consider drafting a mission statement laying out specific goals and expectations. This not only will help you write a better announcement and organize the program, but it also will provide a starting point for finding interns who have the qualifications you think are necessary and outline the areas of interest that will attract them to the position.
In this stage, also think about the tasks that will be available and appropriate for interns and who will be responsible for distributing work, supervising and managing their projects and providing feedback. An intern coordinator with a genuine interest in taking on the additional responsibility can serve as a mentor and gatekeeper, ensuring the interns are neither bored nor overwhelmed and that they are meeting expectations on assignments.
If you are able to hire more than one intern, then consider making available several positions based on subject matter and then find candidates interested in those specific areas. Alternately, you could rotate the interns through the various departments during the course of their time with your organization. Either way, grouping them enables them to develop some understanding in a given area, increasing their competence and, ultimately, their interest in it.
Finally, research the kind of training that will be necessary. Your agency may have standardized training for temporary hires, but you should supplement it with formal or informal instruction that will prepare them for the tasks they will encounter with your organization. It might be helpful at this stage to talk with employees whom the interns will work for and with and asking them what they think will be essential for the interns know before diving in.
Once the position has been announced and you start to interview candidates, think long and hard about how you want to present your organization to those candidates. While it may be tempting to think of interviews as a one-way selection process, especially in this job market, this is your opportunity to sell young people on government service in general and your agency in particular. As you pitch your organization, encourage candidates to ask questions. It may be easier to distinguish insightful and engaged interns by how they react to your comments than by how they respond to standard interview questions.
Also try to suss out their genuine interests and determine if those interests match what the interns will encounter at your organization. These interests don't necessarily have to be subject matter specific, but finding out if they like writing or interacting with people or social media, for example, will help you decide if they will be energized by the assignments you give them or bored by them. While all interns know some grunt work comes with the territory, everyone benefits when the internship involves at least some work they truly enjoy.