Coming up with ideas is good and very affordable.
Testing hypotheses is the natural next step.
There is the common vehicle called minimum viable product.
It is something that delivers the core benefit.
It is for testing the business system.
But this minimum viable product is not a test.
Still you need to bring it in front of people it interact with that.
To do this, people often build a landing page and drive traffic with online ads to it.
They see, if they get purchases, subscribers or whatever.
This is OK, if you go into a transactional relationship.
A spot relationship that only happens to do a quick one-time exchange.
But how many ideas and products demand more than that.
I mean trust.
In this case, you must first build a relationship with your potential customers.
Building relationships and trust requires listening, persistence and consistency.
This is where minimal viable products and quick tests have a problem.
If the idea and product requires a certain level of trust with your customers.
However you need an idea that can spread to have an exchange.
Masters have exchanges in the real world. With postcards, letters and real conversations.