Use the right keywords to be found
Marc Cenedella kindly posted a list of the top 100 recruiter keyword searches on TheLadders.com.
Read that title again. He's giving you a list of the words recruiters type into the database when they're looking for candidates. Marc's list is pulled from his company's records, but if you're looking for the types of jobs found at TheLadders ("sales, marketing, finance, HR, operations, IT and general management"), the recruiters are probably using similar searches wherever they look for candidates.
Do the right keywords appear on your résumé? If your company uses unusual job titles, have you worked a more typical job title into the description somehow? Have you mentioned the specifics of your job that set you apart from the crowd?
The conventional wisdom is that everyone gets their jobs through networking, but your résumé needs to be working for you, too.