I’ve done business in domains where I knew nothing about prior to engaging. In that case, three crucial steps must be taken.
Immerse yourself in knowledge. Take a crash course. Read, listen and watch everything there is to learn on and around the subject. Once you know a little bit, you might know just enough to start asking the right questions.
What does this remind me of? Chances are, there are parallels to be drawn. Connect the dots in your mind and try to apply experiences from another domain, in this new domain.
Surround yourself with an expert. Somebody who knows all the ins and outs, all the pitfalls. Someone who learned by failing in the past, who can prevent you from failing in the present.
The thing is, you can’t judge or evaluate what you don’t know. If you’ve never had an accountant, you can’t verify if the accountant is any good. If you never had to set up a production process, the manufacturers can basically tell you anything.
Learn fast, look for parallels and seek advice from someone you trust (or through someone you trust) who is experienced in the field you are about to explore.