The first step is to define a metric to measure product/market fit. Once you have that, you can systematically iterate toward achieving it.
Even though Marc Andreessen did not coin the term product/market fit, his blog post on the topic remains one of the most popular descriptions of what product/market fit feels like:
Product/Market fit means being in a good market with a product that can satisfy that market.
You can always feel when product/market fit isn’t happening. The customers aren’t quite getting value out of the product, word of mouth isn’t spreading, usage isn’t growing that fast, press reviews are kind of “blah,” the sales cycle takes too long, and lots of deals never close.
And you can always feel product/market fit when it’s happening. The customers are buying the product just as fast as you can make it—or usage is growing just as fast as you can add more servers. Money from customers is piling up in your company checking account. You’re hiring sales and customer support staff as fast as you can. Reporters are calling because they’ve heard about your hot new thing and they want to talk to you about it.
—Marc Andreessen, “The Pmarca Guide to Startups”
Unfortunately, Marc ended that post with more questions than answers and didn’t offer any guidance on how to achieve or measure product/market fit. Sean Ellis makes the concept less abstract by offering a metric for determining early traction that is a prerequisite ...