What are your go-to frameworks for validating your product demand?

I know talking to customers and launching on Product Hunt are awesome ways to validate ideas - but curious to hear what's worked well for others (i.e. Reddit ads, lifetime deals, etc). Eager to learn from the community here. Here's my personal process: https://entrepreneurshandbook.co/validate-your-startup-idea-like-a-pro-my-4-step-framework-cab983374a30