My experience is that you have to know someone in any other field and they will know of things that need to be automated
You also need to find a person in an appropriate field. Not every field is easy for startups to break into.
Example, my partner is a nurse, but works in an office capacity. We've co-developed a suite of tools that make her job so much easier/faster. These tools could probably justify a $100k per annual seat and a small client might buy 20 seats. Yet, we can't really productionize it and sell it because healthcare is basically impenetrable.
So if your goal is to sell a product, think through sales and marketing before diving into the code.