Recruiters can be helpful in that they have corporate relationships in place. The contingency type gets paid between 15 to 33 percent of what you'll earn after you accept your position. The retainer types are paid in advance. They generally work for highly specialized jobs. Job recruiting Internet sites are good sources in your job hunt.
Referrals are really the bread and butter.
Aggressive job hunting usually means sending your resume to many employers. What you're trying to do is get multiple interviews. Do something everyday for your search. Send out resumes and follow up on the phone to make sure that your resumes have been received. However, don't be a pest.