I have a background in print freelancing and am trying to break into the online arena. I'm wondering if it's better to create articles "on spec" and post them somewhere like Constant Content, or if it's better to just advertise my services with appropriate samples? How do I get the best exposure?
I've chosen to advertise my services with appropriate samples. Incidentally, my list of sample articles is one of the most read pages on my site. (I guess some readers are actually writers trying to learn SEO writing techniques, but that's all right with me.) I avoid writing on spec at all costs. That doesn't mean it couldn't work for you. Some people report positive experiences regarding Constant Content and similar sites. So, yes, they may be worth a try. Just don't put all your eggs in this basket. You should think about the best way to make use of your billable time. I believe my time is best spent promoting my services, instead of creating articles that I may never sell. But every writer is different and I'd love to read alternative perspectives on the subject.
It's better to build a platform and your own visibility, so that decent gigs come to you instead of the other way around. You'll never earn to your potential with Constant Content or relying only on publicly advertised gigs. Start a blog. Build your network. Guest post on others' blogs. Get a professional site up if you haven't yet (your own domain and hosting). Try to get interviews setup in your subject area of expertise. If you can't secure interviews, start conducting them instead - on your blog, in a podcast, etc. Write a short report or e-book. Self-publish a short print book. There are countless things you can do to build visibility and a platform that will attract high paying clients. Don't make the common mistake of thinking only about immediate needs and forgetting about that growth. Working for too little up front can set you back years, because it's very difficult to drastically raise those rates once you're already established in a market. Going that route means you literally have to start over when you realize you're not earning what you should be (targeting an entirely different client base).