Do you ever have clients ask you to provide additional services with your freelance writing work -- maybe article submissions, press release distribution, consulting, or something along those lines? Do you oblige, or do you stick to being "just a writer?"
You probably know I used to run a PR firm. A lot of the work I did (most of it in fact) revolved around public relations writing. But there was still other work to be done like consulting with clients, managing campaigns, dealing with media relations, and handling social media services and press release distribution. It made sense to run a full-service firm and market my services in that way, even if writing were a big part of it.
Eventually though I realized a couple of things: 1) I enjoyed the PR writing more than other aspects of the job and 2) I often actually made more on an hourly basis writing than I did with other services I was offering. So I stopped offering those other services and became solely a writer (combining the PR writing with the other business writing I was then offering part-time on a freelance basis).
My story isn't the only option. I hear freelance writers complaining about how they can't find enough work all the time. If you wish you could bring in more work, but you can't figure out how to attract new clients (there's really not a good excuse for that since the information is all readily available, but still...), then maybe you should consider offering more services to your existing clients.
For example, if you write SEO Web content you might want to offer article submission services (since a lot of that content is used in article marketing and submitted to article directories by the client). Or if you're a marketing copywriter who has a solid general marketing background, maybe you should consider offering more thorough consulting services in addition to your copywriting. It could add a new income stream without having to grow your general client base.
Just some food for thought.