Validating an idea early saves months of wasted effort. Start by writing a one-sentence description of the problem you solve and who you solve it for.
Next, talk to five real people in your target audience. Ask about their current frustrations rather than pitching your solution. If the same pain shows up repeatedly, you are onto something.
Finally, create a simple landing page that describes your offer and measure how many visitors sign up. Real interest beats opinions every time.