Depending on your situation, it might be worth earning money from sites like Associated Content, Bukisa, Triond, Helium, etc. Demand Studios has jobs that you select and pays you money for exclusive ownership of what you write. It pays better than the other sites because of this, but they are paying you because they know they can make more money long-term from advertising. So cutting out the middle man long-term makes sense.
Also, you're probably going to get caught on some sites (for using articles you didn't write). If you write articles yourself, I find it gets painfully boring. If you're interested in writing about things like "how to save money on car insurance" and "how do you tell if a boy likes you," you'll make a lot more money from article writing. Specialized areas can also be profitable, such as writing about obscure medical conditions.
I found article writing got extremely boring, myself. I'm not making revenue now aside from around 10 dollars a month. I wrote about two novels (word count) worth of articles. Because I wrote about what I enjoy (philosophy, politics), they weren't profitable. Most of the little money I still get is from boring things like I described earlier.
One trick you can use to find article topics is to go to forums for Associated Content and other sites. Search phrases like "my article made" or "success story." Braggarts like to tell you about how much money they make from an article on topic X. Go make article on topic X, make money. You could also steal the topics and make articles for your own sites. Demand Studios has topics that they screen for SEO value. While there may be some legal issues involved, you could use a Demand Studios account to steal topic ideas. The terms of service agreement likely makes you subject to a lawsuit, so you'd want to use some blackhat methods.