1. having a network of trusted people you've worked with in the past

2. building some sort of public reputation where people seek you out.

They're not mutually exclusive, but #1 is probably easiest for people already in a job. Go to networking events (covid has muted a lot of this, I know, but it's coming back). Tell people you're looking for consulting work. Be nice.

Yes, the answer for most people is not fiverr or upwork. I've known a few folks who've done good there, but they're outliers in my network. And even then, the few businesses I've known that have used platforms like that use it as a test ground, and then go direct with someone they click with.

That said, I've never taken a full year salary in 2 weeks. I have taken my own full year salary matching my early earning days from 30 years ago in 2-3 months now.