Most every job I have gotten has been through personal connections. Usually I followed one friend from job to job.
In the cases where I got photography work with magazines, I researched the market and made contact with art directors. I had been told over and over that you should never bother art directors with phone calls because that will only annoy them and discourage them from hiring you, but I strongly feel that it is personal connections that get you work. I either left messages or briefly talked with the art directors after sending them samples of my work. And I think the proof that I was right was that the only work I ever got was from art directors that I had called.
Of course if I wasn't a pretty good photographer, I would not have gotten the work, but they way I see it is this; if a person has to make a choice between hiring one of two people, both of whom are equally qualified, they are more likely to hire the one they have already spoken to (assuming the conversation went well). Making the slight personal connection of a phone call can tip the scales in your favor.
I hate making phone calls, even to people I know, but with practice, I learned to get through it without throwing up too much. I started out by calling some magazines that I wasn't as interested in working for so that i could fail on my first tries and build up some experience for the magazines I really wanted to work for.
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Never let the weeds get higher than the garden,
Always keep a sapphire in your mind.
(Tom Waits "Get Behind the Mule")