Something that you may want to consider is approaching a major ad agency for some freelance work. You don't need previous experience to do this, you just need enthusiasm and a portfolio.
You can buy a portfolio in any art store. The best choice is one that can showoff tabloid-sized paper.
Next, consider what kind of copywriting you'd like to do. In general, there are 2 streams. The first is general advertising. That tends to include magazine ads, commericals (tv and radio), and creating things like tag lines. The other choice is direct mail. That includes writing letters, brochures, etc.
If you want to write for the web, the best place to find jobs is on the web itself. It's a mix of the other 2 streams, with short and long writing jobs. You'll also want to be familiar with the latest innovations in web design so you can use the medium to it's fullest potential.
If you've worked on ads for clients. put them in the portfolio. If you've written brochures, include those. If you haven't had any ads published, don't be discouraged. You can mock up ads and show those.
Just pick a company that you'd love to write the advertising for. Write phony newspaper ads and brochures. It's fun and the only time when you'll have full reign over the creative for campaigns. Pick a variety of different types of businesses for your mock-ups. For example, a bank ad, a car ad, an ad for a charity, a food ad, and some sort of clothing ad would be a good mix. Try to keep it to a maximum of 8 mock-ups though.
Create mock-ups in Photoshop or Quark if you can. If not, consider hiring a designer to create fake ads for your book. You can even just type it out, although a realistic layout will help you out even more.
The next step is to get a list of the creative directors that work for the agencies in your area. The best way to do this is to pick up an advertising magazine for your area. In Canada, you'd try Marketing Magazine (
www.marketingmag.com) or Strategy. If you're in the U.S., try Ad Age (
www.adage.com). Most of these magazines put out a special issue every year that lists the local agencies and the Creative Director.
Just pick up the phone and contact the Creative Director. Ask if they'd meet with you and look at your book. When you're starting out, the best way to get your foot in the door is to ask for advice on improving your book. If the Creative Director likes your stuff, they may mention hiring you. Look at the first few visits as a way to get advice and strengthen your book.
It can be discouraging but don't give up.
I've been a copywriter for just over 6 years. I've worked at major agencies and worked on everything from TV commericals to web to direct mail. It's often gruelling work with long hours but the money can be good. When you start out, you often don't get paid much but if you've been writing in a different field, that should help you boost your rates.
The only other advice I can add is that there are a lot of massive egos in the advertising world. Sometimes people can be petty and mean. Take the advice that sounds good and ignore things that don't sound quite right. You need a teflon-coated ego to make it in copywriting.
Hope this helps. If anyone has any other questions, feel free to send me a message or post a reply. I'll try to help out if I can.