Ask plenty of questions to gauge his knowledge of the market. A good agency should be aware of trends and hiring practices in your field, and should be able to assess your marketability. Typically, these headhunters deal with candidates who have a very specific set of experiences. That said, we are in a very atypical job market. With unemployment at an all-time low, many employers are struggling to find employees, and are turning to headhunters more frequently to find qualified candidates.
Recruiters are on the look-out for talent more than ever.
Take advantage of this chance to get yourself noticed by a headhunter. Target the best. You can find whole directories of executive recruiters in career offices or at the library. Leaf through a couple to find out which firms specialize in your field. You'll also find that many of the major players advertise in trade magazines and newsletters.