What are the best self-marketing, job-hunting practices for a magazine journalist?

Hello SJ community,

I am a former sports beat writer/columnist who lived largely on game content for about five years (more if you count my school years). Since then, I have transitioned to general-interest feature writing, building on many of the connections I made in the sports universe but also seeking subjects in other realms (entertainment-and-arts, media, etc.).

Lately I've been working for some niche online start-ups, but would like to branch out more for freelance assignments and, if anything tempting pops up, maybe a new full-time staff writing position.

Besides staying active on social media, what's the best way to ensure the right people see my work? And when I'm the one making the first move, what's the best way to introduce myself?

I've tried uploading my resume to general job sites like Monster and Career Builder, but the only responses I get are from scammers offering completely irrelevant jobs. I have also built a portfolio on sites like Muck Rack and Journalism Jobs, but those have yet to fetch any attention. Meanwhile, alerts from LinkedIn and magazine.org occasionally list an enticing opening, but it's rarely anything quite up my alley, namely feature writing for a magazine or the online equivalent.

Where should I be looking instead?

Thank you in advance for any tips.