Having failed the startup game my fair share of times, I've found a more reliable way to come up with good ideas is to let others who need something give you ideas. Work in a specific industry long enough that you learn about the trade and type of problems and solutions needed.

I currently focus on providing services to ecommerce companies, and I get to hear all the time about their pain points and things they wish they had. It's given me a lot of ideas for products to work on and the bonus to that is I already have established relationships with my market, making it much easier to iterate, build case studies, and sell.

A lot of the demographic on HN is engineers. That is an industry. You can start with asking your engineer friends and colleagues what painful engineering problems they face, why nothing they use is good enough, and what they wish they had to fix it. If you find enough people saying the same thing, then you've found a potential market. And luckily engineers are early adopter too.