Here was my journey if it's helpful:

1. I started on elance/guru/Odesk before UpWork came into being. I answered every post imaginable that I thought I could write. This first set of clients became my core group, after each interaction I asked for referrals.
2. I learned SEO and figured out how to rank for longtail keywords or ones not in high demand, like "hire a speechwriter." Yes, this took time and content.
3. I tried cold-pitching various emails of PR firms and others who I thought would need my services--this didn't work too well.
4. While I did do some blogging, I grew my email list instead. I spend more time emailing my list than writing blog posts. I usually get a client or two from each email that I send on a list of about 300-400. You can build an email list by offering a free giveaway to anyone who signs up.
5. While I don't do blogging much on my site, I still did guest posts for other blogs. These were a better use of my time.
6. I'm now going on podcasts to promote my book and services. Podmatch.com is a great place to start.
7. Check out The Freelance Content Marketing Writer by Jennifer Goforth Gregory. It may help you.