I got laid off (company went bust) back in 2009 and started freelancing. I got some referrals from friends and just kept going. I found plenty of work, mostly word of mouth and with long-term relationships with customers.
I never had much trouble finding customers. I focus on solving business problems. I prefer working on legacy code (which more often means “abandoned” rather than “old”). I don’t specialize in any particular stack or technology, I figure out how to fix things.
I used to get quite a bit of overflow work from software dev shops and design/marketing agencies. They either need work or they have done the prospecting and give an intro. If I had to start over that’s where I would start.
In 2014 I signed up with an agency to represent me. They do marketing, legal, customer service, invoicing, payment. I have found that worth their percentage because they built a premium brand that benefits me.
I have some articles about freelancing on my web site, link in profile.