It's a lot like dating. Pick the right place at the right time, then get your name known to the right person ... you might get some interest.
Seriously though, word of mouth ... friends of friends ... people who know people and sometimes they're lucky enough that a real catch finds them, not the other way around.
Advertising works too, but you have to get your ads where people can see it and it's permitted. I know a massage parlor that used to take out ads in college and university papers which worked for them.