Authors like Rob Walling and Pat Flynn or course creators like Amy Hoy have these ways to try to figure out if there is a market for an idea.
What is your current favorite hack for figuring out if people are willing to pay for something before you create an idea?
Talk to people.
If that sounds too glib, and you really want something of a "hack", I'll offer up what Steve Blank calls "the million dollar question." If your domain isn't enterprise software, you can probably find a way to riff on this and adapt it to your needs.
“I ask them, “If the product were free, how many would you actually deploy or use?” The goal is to take pricing away as an issue and see whether the product itself gets customers excited. If it does, I follow up with: “OK, it’s not free. In fact, imagine I charged you $1 million. Would you buy it?” While this may sound like a facetious dialog, I use it all the time. Why? Because more than half the time customers will say something like, “Steve, you’re out of your mind. This product isn’t worth more than $250,000.” I’ve just gotten customers to tell me how much they are willing to pay. Wow.”