Freelancing is similar in some ways to blogging. For one thing, you get to work from your own home or office most of the time. But there are a few important distinctions. First, if you're thinking about freelance writing, chances are you need to have more experience than the average blogger. Many freelance writing positions cover specialized topics for online publications and many require expert knowledge on the subject. However, if you're passionate about things like travel or food and know how to write, a freelancing job can provide you with a good income.
Along a similar line, you might also consider self-publishing your original work rather than working on contract-driven tasks. Self-publishing offers many of the same benefits as freelance writing. This additional step is risky, though, because it requires marketing work to your target audience so they'll buy your work.
Writing's not the only way to make money freelancing, of course -- anyone with graphic design or programming experience can find contract jobs that pay well and provide challenging work, too.