The internet killed the knowledge advantage and is killing the skills advantage. Reputation built through relationships is the one that survives, on top of real competence.
The idea
Professionals used to win on three things. The knowledge advantage: you had information nobody else could get. WebMD, Wikipedia, Zillow and Khan Academy ended that. The skills advantage: you were one of the few good plumbers or lawyers nearby. Communication tools and gig marketplaces made location matter far less; my own book was produced by people in DC, New York, Houston, Denver and Kiev. What's left is the reputation advantage, and given how humans are wired, it isn't going anywhere.
The caveat matters as much. Relationships get you referred and open the door, but being good at what you do is table stakes. As Jerry Della Femina put it, "nothing kills a bad product faster than good advertising."
How to do it
Get genuinely good at the work first.
Assume clients can find your knowledge and skills somewhere else.
Invest in the thing they can't find elsewhere: people who know, like and trust you.
Example
When I hosted large tech meetups, I'd see the same people "networking" every month for startups that were still napkin sketches. My own referrals came out of the blue because I was a solid freelancer who happened to know a lot of people. Both halves mattered.
Watch out for
Grinding for an introduction to work you can't deliver. The intro is a lost cause if you bomb the project.
Escape the Commodity Comparison: If clients can compare you line by line with someone cheaper, you lose the race to the bottom. Relationships make you hard to compare.
Know, Like and Trust: People work with people they know, like and trust. Trust comes from shared context, previous engagement and endorsements from people already trusted.
Relationships Are Your Most Important Asset: The best careers and businesses are built on personal, authentic relationships, because people work with, hire and help the people they know.
The Human Premium: As AI floods every channel, trusted human relationships become the main filter for attention. When you can't trust the channel, you trust the person.