I've been doing Facebook ads for 9 years. My team and I are a white label agency so we do the media buying for creative shops, designers, content marketers, etc. So I didn't land any client. I partnered with the folks that did. I got the partnership by putting out a ton of content on Youtube (Over 20 hours worth), through doing a 30 episode deep podcast on running an advertising agency, and being super helpful in a number of Facebook groups, Linkedin groups, etc. for years.
Tl;DR Content Marketing + Networking