Chasing listed jobs is a mug's game for two reasons: (i) you need to compete with a mountain of applications, and (ii) people often list jobs that they aren't entirely serious about filling. Even if you have a strong resume and put 30 minutes into writing a good cover letter for each applications, the odds really are against you in this case.
Factor (ii) is still a problem if you get an interview because many organizations put multiple random barriers ahead of applicants. For instance, if you don't pass some test or flub a question or one of the fifteen people who talk to you just doesn't like you on an animal level you've wasted all the time you've put into the process.
Anybody who's using a recruiter, on the other hand, really wants to fill the position. The odds are in your favor because the recruiter is going to walk if the company keeps putting candidates through the gauntlet and rejecting them.
So how do you get people to call you?
Be active on the web. For me that's meant developing a few side projects and also developing connections and adding some content to LinkedIn every day... Even when I'm not looking for work.
If you get yourself known you can quit wasting time looking at job boards.