Part One: Strategy · Where demand comes from
Every extra kind of customer looks like extra revenue. A product stretched to fit all of them fits none of them well.
It starts innocently. A quoting tool is built for small freight forwarders, where the person who talks to the customer also sets the price. A larger firm signs up and asks for approval steps, because its quotes go past a pricing desk. Another wants customs paperwork. Each has money and a reasonable need, and saying yes feels like growth.
Two years later the product serves people in three different situations from the same screens. The small forwarder wades through approval settings meant for a department. The large firm finds its approvals half-done. The front page cannot say who the product is for, so it says "for logistics teams of all sizes."
The pull toward everyone is strongest inside the company. Sales is paid on deals, and a deal is a deal. Investors like a large market. Nobody is rewarded for the customer who was politely told to look elsewhere.
The useful line is drawn by circumstance, and it is found more than decided. The same forwarder can be on either side of it in different years. Look at the customers who are happiest and ask what their situations have in common. Usually they are the ones who care most about the thing the product does that nothing else does. They are who it is for. People in other situations will be better served elsewhere.
The quoting tool's front page could say: "If a quote needs sign-off before it goes out, you will be happier elsewhere." The pricing desk leaves. The two-person forwarder reads that line and knows the product was made for the way she works.
Therefore:
Find the people whose situation makes them care most about what only your product does, and build for them. Say plainly who it is for, specifically enough that the wrong people can tell.
In practice. List your ten happiest customers and write down what their situations share. Then write one sentence that begins "This is not for you if..." and put it where a newcomer will see it.
Goes with. The line follows from being DIFFERENT WHERE IT COUNTS (8). Holding it lets you do ONE THING DONE WELL (6) and keep A POINT OF VIEW (17).