I started contracting at about the same point in my career. I'd been at four different companies, two of them pretty big places where I took on mentorship roles. Over time I'd built up a list of colleagues (a rolodex, if you will) who would come to me with system design and architecture questions, both for work and for side projects. Eventually, some of those side projects grew serious, and I transitioned to freelancing gradually during a period when I was otherwise taking a break.

I've never done sales, and I'm deathly afraid of the need to do that some day. But my colleagues and friends keep hiring me and keep getting promoted, so we're good for now, I guess.

Not sure if I have any concrete advice beyond: take those coffees every time,and keep in touch with talented colleagues.