Ask HN: Resources to Understand Market and Demand

I am at a point where I am good enough to build apps and services but inexperienced enough that the only problems that I can address with said apps are generally things I have friction with.

Do you use any tools to understand what companies are lacking, what they're looking for in terms of software/services, general trends? It is often said that if you solve '1% efficiency' issues in a large but unknown sectors you stand to gain for it. Well, how can you identify these issues, or more generally where money is being spent on by companies? Any public information or way to extract this? Thanks