Social media marketing seems to be the best bet, as near as I can tell...building an audience, establishing credibility and offering your services.
Marketing is all about defining your target audience (for me, low-income writers looking to outsource proofreading and editing on a budget.) and finding the spaces they're likely to be in. It isn't about shoving links in people's faces like clowns throwing pies, but it's about having your links available and tailoring your social media to funnel people in. I make posts about what I'm doing at work, what kind of editing I do, and I try to make myself relatable to my target audience.
If people like you, they're more likely to want to hire you- assuming you're offering a gig that lines up with their needs.