I would like to shed a little light on freelance copywriting. I have been doing freelance copywriting for a couple of years as a side activity. I am not a creative by training, my degree is EE and I have been a freelance software developer for 15+ years.
Here's what I do:
http://www.donwallacewriting.com
First of all, and this comes indirectly from Peter Bowerman in a private consultation with me a few months ago, don't even WORRY or BOTHER about ad agencies. They won't even be interested in anyone who doesn't come from the "correct" creative background. And forget courses and lengthy "apprenticeships".
The reason I don't like the idea of courses and I don't like the idea of working through ad agencies is because both ideas assume that you are not ready to deliver a billable product to customers, who are ultimately the companies who need copy written for their marketing and internal needs. In other words, saying "you need a course" is implying "you have nothing to sell currently". I would bet that you probably DO have skills that you can sell right now via written deliverables, and then, it becomes a marketing challenge, not a readiness issue.
If you are a decent writer, *and* you are willing to learn your client's marketing and sales objectives, you can write well enough already to satisfy many customers' needs. I will explain below.
The reason Bowerman and a few others emphasize cold calling is that you basically have few ways to get your foot in the door. Either have someone else vet you or work "through" someone - an agency - or, bat for yourself and make your own contacts with businesses that need copy written.
My experience in IT is that headhunters and brokers "own" the job market there, so if you have an unconventional or varied background, it's a liability. Similarly, I would expect that an ad agency wants to see a pedigree and exacting experience. And depending on middlemen to put food on your table REALLY stinks. That is a matter of basic survival principle.
Here is what I have found really works well:
Try, as much as possible, to be a niche specialist in a particular type of business. Which business? Figure it out, that's your homework. For instance, the role of copywriting guru for North American podiatrists and food specialists is wide-open currently (probably.)
But select a type of business that you either really know well, or which you can learn.
REALLY knowing one line of business - my specialty is small software vendors- helps you do two things: 1) sell yourself to your prospects (they LIKE knowing that I am also a programmer and I "get" what they are doing out of the gate) and 2) that knowledge helps you to produce copy that will really please your clients. Also, being specialized is an integral part of self branding. It's much easier for clients to justify spending money on a specialist than on someone who has done pro bono copy for a dozen different unrelated lines of business.
I think networking could work, but, it's not really my style. I think when you drill down to the level of specializing in a line of business, you will find that you pretty much have to drum up interest yourself and you're not going to be able to trade leads that productively with other writers because you're in different niches. But it's really not that hard to do so. All of the business I have garnered has been "passively" found by lurking message boards. It's actually surprised me how "easy" a sell copywriting is when you establish your value with clients, and how *hard* many other types of freelance work are to find customers. (Example, I have basically given up on marketing myself as a programmer - the bloodsucking pimps AKA recruiters own IT.)
Lastly, in copywriting some humility is called for. You'll probably never get a byline. You write to serve your customer's needs, about some subject which you may not care about personally, and not to make yourself feel fulfilled. Some people think those things are just "terrible." The rates and fees that you can charge in copywriting makes up completely for those factors. I'd rather be an unknown billing good rates "ghost writing" my client's marketing materials than feeling like a bug splattering on a windshield chasing the creative opportunities that everyone else covets. But that's me.
I *need* to cold call sometime, but that's probably when my present (programming) contract is done.
Here is a mailing list that was created just for freelance commercial copywriters:
http://groups.yahoo.com/group/wellfed_writers/