How can this attribute be developed and nurtured during the earliest start-up and development of the business.
Your brand must conjure associations beyond the clothing itself.
Fabric is only fabric. Attractive design matters, but market competition is enough to drive down prices. If you intend to ask a premium, then your product line must SUGGEST more than it literally is.
Eventually, certain brands reach maturity and can point to an established reputation or high-profile adoption by the rich and famous.
But you can start out by honing a brand "story" that captivates attention. Parts of that story are visual; others are verbal.
Naming -- which is a large part of what I do -- is crucial when it comes to instantaneous unconscious communication. The right name tells your story for you on first contact with investors or consumers. Thereafter, it echoes in the mind, resonating with associations people bring to your product from their own experiences. Those associations add value.
This is true whether you're a luxury brand or a maker of upscale outdoor gear like Patagonia, which takes its name from rugged South American highlands.
In addition to your brand name, I would recommend paying close attention to all of your written copy. Make it unified and stylish ... in whatever way best fits your product line and intended audience.