Instead, start by understanding how your skills can profit a particular business. This can kill you in an interview. There is a big difference between looking to get a job, and offering to do a job. A good headhunter has a tremendous edge because he selects and prepares the candidate who can walk into the meeting with the employer and do the job, right there in the interview. Obviously, this takes some research.
Headhunters do a lot of research, and it makes all the difference in the world.
Unlike most job hunters, headhunters don't sit by the phone, waiting for someone to call back on a resume. The headhunter seeks to control all aspects of the deal, so that every candidate he submits hits the ground running in the interview and is desirable enough to hire. Make doing the job in the interview your goal. The interview isn't an experiment or a fact-finding mission. Don't go on an interview unless you are prepared to control it, and to demonstrate your ability to do the work.