

Not gonna lie: my first customer was a place I interned at when I was a student. So I knew who to contact, and what the potential value of my product was, as it was tailor made.
After that I started with contacting other companies via linkedin. Here my “trick” is to contact managers with an engineering background, as they more than often speak my language. In other words: I look for people who (a) have a technical understanding of their production process and (b) are high up enough on the corporate ladder to have a say about spending. Weirdly enough: a rare combination.
Wifipassfinder? I’d guess you could sell the technique to a product like PDQ. Or even metasploit. But that’s just guessing, I know very little about that market.