Dominate the narrowest possible niche of the most demanding customers so completely that their trust becomes your reputation, then expand into larger adjacent markets off the credibility you earned there.
Patagonia
Patagonia is an outdoor apparel company that began not as a clothing brand but as Chouinard Equipment, Yvon Chouinard's climbing-hardware forge. Its through-line is that a tiny, credible foothold with one demanding customer group (Yosemite climbers) became the launchpad for a far larger business: a clean study in winning a narrow beachhead first, then expanding off the reputation earned there.
Beachhead: from hand-forged pitons to an apparel brand
The problem. Chouinard needed climbing gear that did not exist to buy, and he had no capital, no factory, and no market beyond a handful of friends. In 1957 he taught himself blacksmithing on a used coal-fired forge, a 138-pound anvil, and some tongs, forging his first pitons from an old harvester blade. The constraint was severe: he could make only about two chrome-molybdenum steel pitons an hour, so any business built on them had to start impossibly small.
The approach. Rather than chase a broad market, Chouinard dominated the narrowest possible niche: reusable pitons sold to Yosemite climbers who trusted the gear because he used it himself on first ascents of routes like the Lost Arrow Chimney and Sentinel Rock. He sold them for $1.50 each, formalized the operation as Chouinard Equipment with partner Tom Frost in 1965, and then extended off that trust into apparel when a durable rugby shirt he bought in Scotland in 1970 for climbing drew orders from all his climbing friends.
How it solved it. The beachhead compounded: by 1970 Chouinard Equipment was the largest supplier of climbing hardware in the United States, giving him deep credibility with a small but intense customer base. That reputation carried directly into the clothing line he founded as Patagonia in 1973, a more scalable business than hardware, which was only marginally profitable (the 1972 catalog even promoted aluminum chocks that deliberately cannibalized the piton trade to protect the rock). Patagonia expanded not by targeting a broad market first, but by owning a defensible niche and then moving into an adjacent, larger one where its authenticity transferred.