Sell stuff on eBay. Start by selling your own extra stuff. Then, once you get a feel for selling your extra stuff, go door-to-door in nicer neighborhoods in your town. Develop an eye for what will sell and what won't (old laptops, for instance, could be a gold mine–if you know how to format them to get rid of the previous owner's personal data.) Sign a contract where you take 25-30% (or more) of the gross sale. Your customers will be happy to get cash for their old junk, and you'll make some good money selling other people's stuff.
Become a freelance article writer. It may not pay well, but there is a growing demand for this. Write 200-300 word articles and submit them to article directories. Potential clients include bloggers, marketers, and small businesses. You can write articles in a niche in batches and sell them as a package to one or more clients, or you can offer your services for hire per word or article and let your client give you direction. A foundation of keyword research is important to succeed at this job (unless you're just taking direction from a client), but keyword research is learnable.
Write articles for magazines or other publications. If you have a background in journalism, or just a passion for it, you can try your hand at submitting articles to publications. Don't just randomly fire off articles, however; have a plan and, preferably, a contact at the publication you wish to submit to. The good news is that there are publications in pretty much any niche you can think of.
Transcribe audio files. An easy job; doesn't pay well, but also a quick way to make some money. Sign up on eLance or oDesk to start, and/or advertise your services in entrepreneur forums. Requires good hearing and a good command of the English language. You may also want to invest in a foot pedal if you plan to transcribe often. Make sure you know how to transcribe interviews before you start your first job.
Become a virtual assistant (VA). There are entire books written on how to become a virtual assistant, so this job is definitely worthy of more research. My advice: Focus on one niche. Also, reach out to potential customers directly and let them know what you can do for them instead of hitting up freelance web sites. Finally, you may want to consider online resources that provide training for up-and-coming virtual assistants.
Do some videos to promote affiliate products. Enjoy making silly videos? Even short, silly videos can sell products online. Find a product worth promoting that has an affiliate program, then target your video toward potential customers of that product. In your video summary on YouTube, place your affiliate link for the product, and after the video, do a 30-second still frame showing a short URL where people can buy the product. If your video is funny, informative, or useful, you may sell some products. Big tip: Try to promote a product that makes you a fair amount of money for each sale, but doesn't cost a whole lot for the potential customer.
Write an ebook targeted to people who need help. Sellers charge up to $97 for ebooks as small as 12 pages. The key? Finding people who are incredibly desperate for the information you provide and then doing good research to find a real solution to their problems. The result? Happy customers whose problem is solved, and money for you — a win-win situation! Caveat: It may be tough to find a real desperate buyer niche. Here are some hints: When were you last in a situation where information would have either saved you a lot of money or a lot of pain? Has someone else close to you been in a situation where they could have used information to avert pain? Think legal, medical, and financial niches.
Help local businesses develop an online presence. Local businesses are struggling. Many have websites, but aren't getting any results from them. Others don't have websites at all. You can help by learning search engine optimization, how to set up an email list, and more, and then implementing these for local businesses. If you typically hang around geeks, web marketers, or the Web 2.0 crowd, you may be surprised how many business owners are 10 years (or more) behind you! If you can deliver results, business owners will happily pay. Find customers by going door-to-door.
Learn Wordpress, then offer to install plugins and upgrade it. I hired people from online to upgrade my blogs and install new Wordpress plugins. They charge $5 to upgrade a plugin, since most plugins only take a few minutes to upgrade, and great for me, since if anything breaks, they get to clean up the mess! You can make this a full time position; there is a ton of demand for these services. Find customers by contacting bloggers directly. Get references from bloggers who understand the value of outsourcing these tasks.
Become the go-to person for installations of a particular piece of software. Anything from Amember to Quickbooks is fair game here. In the hosting industry, iDevAffiliate and Plesk Billing were the pieces of software we would have paid a lot of money to have someone else deal with. The more niche and more complex/annoying/frustrating the software, the better! Even if the software company offers free installation, you can make hundreds or thousands of dollars training business owners or their employees on its usage. Focus on one piece of software and become the trusted expert. Create videos and tutorials using screencast software like Camtasia to increase your profitability; this may also lead into a niche product that you can sell.
Interview other people and sell the interviews. The key here is to understand a pain point that people are experiencing, interview an expert, and ask the expert the questions that the people experiencing the problem are having. Then create a small website and sell the interview. There's more to this, including having good copywriting skills so your website sells the interview well, and knowing where to advertise, so don't expect to immediately pull in hundreds of dollars. That said, it's a neat way to quickly create a product. Get the interviews transcribed, then string a few interviews in the same industry together as a membership site or bundle that you can sell for more money.
Become a freelance "web geek." From configuring a shopping cart to installing and tweaking blog themes, there are virtually unlimited projects out there for geeks who enjoy working with small business owners to get them up and running online. Find people looking for web geeks on the Warrior Forum or other places where entrepreneurs gather.
Enter logo and design contests. Fancy yourself a good designer? Try your hand at creating a logo or other design that a company loves! 99 Designs is the most popular marketplace. Beware, however; you won't get paid unless your logo wins against many others, which makes many designers unhappy. In my opinion, this is a great way for a budding designer to build a portfolio and learn quickly what clients love.
Create Twitter backgrounds and e-covers. Competition is stiff, but if you are a savvy designer, this is a good way to pick up extra dollars. Even better, if you are an artist, this is a good way to make your art skills pay off. Consider that every design will need to have a reason why the customer should buy the book or follow that person on Twitter to have a real impact. Twitter backgrounds, in particular, are in hot demand right now.
Submit websites or blog posts to social media websites. Not very exciting work, but in high demand from bloggers and small businesses. This involves setting up accounts on all of the social bookmarking services and then bookmarking your clients' websites or latest blog posts to help them get more traffic. You may be competing against software that does this, but in many folks' opinions, it's better to have a real person do it. Even better is if you can goose your accounts with plenty of friends and become a star on a few of the services; then every site you bookmark has higher credibility and you can charge more.
Edit audio for others. This is something that is fairly easy to learn and also in high demand. Get the hang of editing out "um"s and "ah"s from audio. Even better is understanding the "flow" of an interview conversation and editing out portions that don't make sense. Finally, learning to find and add intro music really gives podcasts that professional touch. Advertise your services on oDesk or eLance. I pay people to do this for the podcasts I am setting up, and it's a job that can definitely be done from your house.