The most common misconception about recruitment agencies is the idea that recruitment agencies find candidates work. In most cases, recruitment agencies do not find jobs for people, rather they find people to fill the positions that their clients are wanting to fill.
Choose carefully the jobs that you want to apply for. If you are applying for a job that you don’t meet the minimum requirements for, you will not get the job. They will not consider you.
Recruitment agencies also keep a database of candidates, to enable them to fill positions without even advertising. These databases can grow rather large, so it is important to make sure that your CV contains keywords relevant to the positions you would apply for, and that the CV is readable by a computer (i.e. not a scanned image). Recruiters will put in keywords when they are searching for possible candidates for a position, and if your CV does not contain the right keywords (skills, qualifications, job titles, etc) then it will not come up in their searches.
Recruitment agencies normally do not charge candidates (be wary of any that do try to charge a candidate, these are usually scams.) Their fees are paid by the company that hires you when they have placed you, meaning they get paid when they get you a job. All you have to do is be a great candidate!
Recruiters can be incredibly useful in helping you with your job search.