How do I test whether people actually want my idea?

You already test your ideas, which puts you ahead of most. The harder skill is designing a test that truly proves whether people want the thing, rather than one that just flatters you with polite interest. The trap is that people are kind. They will say they like your idea, and that tells you almost nothing. Real demand shows up as cost: time, effort, a signup, money, a spot on a waitlist. Design your test around an action someone has to actually take, not an opinion they can freely give. For your next idea, ask what small real commitment would prove someone wants it, and build the test around that. A pre-order beats a compliment. A signup beats a nod. Make people spend something, even a little, and you will finally know the difference between interest and demand.