‘Build it, and they will come’ is the worst approach to building a product.
Here are some approaches that work:
In the case of SaaS, selling the concept before building it works great.
Buffer, the popular social media tool, started this way.
They created a landing page and showcased the product Joel, the founder, wanted to build.
When people clicked on the buy button, they were taken to a thank you page, where they mentioned the product was not ready yet, and they would be in touch.
Pre-sell and then building is another strategy that works well.
Send people to an offer page and pre-sell.
If enough people pay, build it.
Freshdesk, the billion-dollar brand, used this strategy before launching its business.
For building info products, create an interest list.
Ask your email list, and build it if enough people show interest.
In this case, your interest list (those who say yes). This list should be 4-5 times the numbers you want to sell to make it work.
Kickstarter and Indegogo also work well to showcase a product, presell and promote your idea.
Pick an approach that is relevant to your scenario.