I recently got an email from a guy who asked how I was successful in freelancing full-time. As readers of this blog know, I am not, but it did give me a chance to put some thoughts down in writing. Here is the gist of it, at least in my experience.
I pick up work on a somewhat regular basis, but not a lot of it, I'm usually just working on one job at a time, and it's all different stuff. Last year I did a lot of freelance flash illustration, this year it's some comic work. All of my jobs I get are done through networking. I routinely send friendly emails to people I know that are in position to hire me, recommend me or at least keep me in mind. Sometimes it works, most of the time I get no response. It's a constant struggle and even projects I work on that are just pitches often go nowhere, even when I work with an established professional with a known name. Publishers are pinching their pennies and it's harder for everyone. Also, every so often I get a random email from other professionals who have seen my stuff, or were recommended to me by a friend. There is no right way to go about it, I wish I knew the secret so I could freelance full-time myself. Sorry I couldn't be more helpful, but I would suggest to just network as much as possible and don't hesitate to send out emails to anyone, I've cold-emailed lots of people, and sometimes they get back to me.
Now, in my case, it's important to note that I also have an extremely low self-image about my work. It's flattering when writer A, who has books out with Image or Boom or another publisher emails me about working with them, but I always think they assume I work for free (which is sometimes the case) and they want me because of that and not because they like my stuff. In reality I assume it's a mix of the two, the work is good enough, and I work for free, or at least it seems that way.