If you want to earn extra money then there are at least 2 things you can do that I can personally tell you that they work if you follow through with them. Neither one is super easy to do but both are a modest amount of work and you can earn a nice side income with either if you like. Now if you are willing to work like a dog at this then you can also earn a full time income from either of these as well.
First of all is publishing on the internet and making money from the content you create. There are a thousand ways to do this, for example, Hubpages, but I would suggest that you start out with a blogger blog and lay down a few posts each day. You have to pick good keywords to target with these posts if you hope to make any money, but after that it is just a matter of laying the posts down and then building a few key links to those posts. Keep building and in time, traffic will show up.
A lot of traffic will show up that you did not anticipate. You might have been targeting the keyword “earn easy money” but you ended up getting traffic for the keyword “earn cash online.” So what you might do then is to make a new post and title it “earn cash online” and then you will notice that the search engines will send you even more traffic. This is basic data mining using your traffic logs and if you keep doing that over and over again and targeting new posts with new keywords then eventually you will build a large site.
Now if you have this type of website and you keep building new content and links to your stuff, then you will make money. You can do that in a number of ways, one way is to put ads on your site, another is to sell affiliate products. But the whole key is to get lots of search engine traffic.
Now the other way to earn some extra money is to write articles for other people. If you go to a freelance site you can write articles for other people and make good money doing it. I have made between 3 and 4 dollars per article, which does not sound like much, but I can easily crank out about 12 articles in less than 90 minutes while I am just sitting and watching television. If you do that every single day then that is a pretty good part time income. Do the math, it’s not bad at all!