If you want to really make a living with freelance writing, you can start with the types suggested so far. But you should also look for clients who will come back again and again. The only reason I make decent money for my time is that I've worked for repeat customers so I haven't had to spend too much time chasing after business.
You should set up a website to promote yourself and your services. Design it so that when a potential client arrives on the home page it is perfectly clear what you do and why you are the one to do it. Make it easy to contact you as well.
Check this previous article " How to Make Money Freelance Writing ".
Your website URL should be on your business cards of course. I tend to stay home and therefore don't mingle with prospective clients much, so I don't have business cards at the moment, but they are probably a good idea. I did recently get several small projects from a local businessman who is launching a travel-themed website, and maybe it would be helpful to have a card to give someone in a case like that (but I managed without).
Freelancing writing for print magazines is a tougher market to get into. Some still pay as much as $1.00 per word. When, instead of $50 or $100, you can make $1,200 for medium-length article, the competition is fierce. It is easier than ever to try though, because almost all of the print magazines that accept freelance work take submissions or queries by email now, and many of them post their guidelines on their websites. Soon I will attempt to sell to the places that pay $0.50 per word or better, but so far my best sales to a printed newsletter paid just $0.10 per word.
Much of your freelance work is sold with all rights, and if you don't ask you should just assume this is the case. That means you are paid once and you can never again use that article, even on your own website or blog. I can live with that as long as I make a decent rate. And in any case, if I write an article about backpacking I can always write another one in new words and from another perspective.
Sometimes a buyer pays for "First North American Serial Rights" (FNASR), which means they are buying just the right to be first to publish your article. They may or may not specify how long after publication you are free to sell the article elsewhere, but you definitely have to wait until it is published (not just paid for). I recently sold a couple articles to an online writing magazine that buys "first electronic rights," meaning I could sell the same article to a print magazine and, as soon as the buyer published it online, I could sell it again online.
Being able to sell your article again means getting paid more than once. Some authors sell their articles many times. Just make it clear to subsequent buyers that they are only getting "reprint rights" when they buy it.
It can be tough to make money as a freelance writer! I've had a good start, but then I had some advantages. I had a book published by a major publisher and I've been writing for my own websites for almost ten years now. Setting up a website to promote my services took me only a couple day's work and $12 per year to operate it.
I also have other sources of income (I have become a strong believer in diversifying income sources). If you really have no experience, keep your day job and expect to work at your freelance writing for a long time before you make a living from it.