One final way to promote your work is through social media like Facebook, Twitter, LinkedIn, and Google+. All of these are ways you can generate interest in your work. They also allow you to set up free pages to promote your freelance writing.
And finally, you can do any combination of these things. I prefer to use a freelance website because I feel it saves me the time and work involved in marketing my work. It also gives me a chance to bid on jobs posted by people who were not initially interested in my work. However, some people may prefer to go it on their own to avoid commissions and upgrade fees. If you go it alone, you also only need to take the time to write out a bid for people who have already expressed an interest in your work.