Google "freelance writing" and you'll come up with over 2.5 million hits. Freelance writing is a hot topic. People want to know how do you get started, where are the jobs, how do you make it work, etc. My biggest piece of advice to any newbie and, actually to the established writer as well, is do your research and research often.
Newbie writers need to find out different perspectives on the freelance writing field, its lifestyle and job news and information. Vets should keep up on the latest news on the field and in media in general. Those who are genre specific - magazine writers, tech writers, book writers, etc., also need to keep up on their specific area. Shake ups in the industry can affect your work flow or open up new opportunties.
I mentioned WritersMarket.Com earlier. For magazine writers, keeping up on the latest in the industry is essential. One day your contact at the magazine may move to a new position or even a new magazine. Sending a query to the wrong editor is a sure way to sink.
What industry publications do you love?