If you want to become a Freelance Article Writer, I don't want to discourage you in any way. However please be advised that there is a ton of competition currently in this arena. I mean there are tens of thousands of people right now, many with an established reputation that are freelance writing for others. However the demand for this service is also extremely high so if this is something you want to do, let me give you some quick pointers that will help you excel in this area and stay in this business as long as you want. I also suggest not getting into this field unless you have a solid grasp of the english language, can type at a decent rate and are willing to spend a lot of your time doing client work. Okay I've said it, lets get into the meat of things now.
The first thing you should do if you want to become a Freelance Writer is get a basic grasp of Search Engine Optimization both from the on-site and off-site perspective. This means you should lead by example and have a website of your own you refer people to. Make some samples, since in most cases you can't use your client's content since you'll be creating it unique for them, and post them on your website. This will go a long way in establishing trust with potential future clients since they will want to see samples of your work which will build essential trust. Also make sure your website is neat and orderly. And spend some time getting links to your new website and keep a contact form on it so clients can contact you right through your website.
Another tip is not to be the cheapest writer out there, but the best. People will easily pay double for your services if you are giving them content that will truly help them dominate their market.
The standard rate for a 500 word article is $6.00 per article. However why not charge $12.00 per article but make their articles around 1000 words with good upper level english implemented in them. If you just wrote 3 articles like this per day for clients you'd make $36.00 per day. No that won't get you rich but it could cover a lot of your bills each month or put cash in your pocket while you're going to college without having to say "Want fries with that shake?". Not to mention you're working for yourself at your house which will save you gas and wear and tear on the car.
Once you get a decent client base you can start charging more for writing longer sales letter for people as well. You can make thousands of dollars for writing long-copy once you can get people to trust you. Billions each year are made marketing products and services on the net, and each retail store will need custom descriptions, each product will need a sales letter and just about any website that wants to make sales will need quality articles written for it and submitted to the top article directories. Writing is a very dignified job that can earn you a great supplementary income if you approach it right, and it's nothing to be ashamed of. Just make sure you collect payments for new clients up front if they find you on the web.
As far as getting clients, you can solicit your services on Elance, Scriptlance, Odesk and Guru just to name a few. There are actually dozens of sites like this which free lancers aggregate at but these are the main ones. The key is to setup a great website, get some jobs from these sites and let every client you know about your main website. This way when they need more work it will be very easy for them to find you and this is very important. Whether you're working full-time or going to school, Freelance Writing is a great way to earn a supplementary income and no official credentials are required. You'll eventually build your biz by word of mouth and good customer service.
Don't let anyone tell you this is a bad business. Millions of Internet Marketers are going to need tons of content written for them over the next decade. Throw yourself in the middle of it all so you can collect an extra paycheck.