Ask HN: The first client. Any recommendations?

I started a blockchain consulting company and did present 2 proposals to interested clients, that were unfortunately rejected. We are still new and we are embarking on our pro-bono work with charity so all is good and things are getting rolling.

I would love to hear your experiences about getting the first paid client in any industry, how did you manage to convince them to work with you without a track record and any general advice you would give?