Few ideas:
– have a killer CV and interview style that they can sell
– if you have neither, ask for help.
– make the CV concise, easy and fast to read. It’ll get maybe 30 seconds attention. It’s just a tool to get you to a) show up when they search their database, and then b)to get you invited to interview.
– don’t be shy about flagging up achievements (eg sold loads of something, saved last employer loads of money, delivered a project ahead of time & budget etc)
– never lie. But present things in the most positive light possible
– by all means remind them you’re there sometimes, but don’t call every day, don’t be a nuisance. They’ll think you’re either an idiot, or desperate, or both
– make sure your phone number(s) and email are on the CV (shouldn’t need saying, but you’d be surprised how many people forget). Don’t just put them on the cover letter, these are rarely filed
– carry your mobile all the time. If you can’t speak when they call, say so & agree a time to call back
– ask the agency what sort of positions/clients they work with. Are they really active in your area of interest? If not, ask if they can recommend another agency who might be more appropriate
– work with them, return their calls/emails, even if it’s just to say “no thanks”
– don’t rely on just one agency.
Source – 11 years of working in the business. They were the only industry that’d have me!