Joseph's answer is spot on.

Clothing is about the story you tell about yourself. People wear Kmart because it's affordable. It suggests nothing more than an appreciation for reasonable pricing.

Marc Jacobs however boasts of something entirely different. You have taste. You have style. You are somehow "in" and care about fashion.

Entirely different story and entirely different audience.

If you intend to have a high end brand, you want to ask yourself what high end means and how you aim to create that. It takes time to create this persona.

Here are a two, main things to consider:

1- Design: look is everything. From the clothes to the way you showcase them.

2- Product placement: where are your clothes showing up? What editorial and on who? This is huge. And what story are they telling about your clothes? The story isn't only told through words either. Aesthetic plays a major role in this as well. We are trained to believe that when things look a particular way, they mean a certain something. Thus, figure out what you want the world to believe about your brand and consider how we've been trained by mass media to believe these things (considering placement, look, feel and people wearing them).

3- I had to get a third in there. Price and availability also tells a story. Less is sometimes more in terms of quantity and higher implies better quality. Again, it's about the story. Consider, though, companies like DSTLD (https://www.dstldjeans.com/). They boast of designer products at less inflated fees. The jeans aren't cheap, but seemingly discounted. They tell you they save you money by giving you what let's say Ralph Lauren would provide without the inflated prices. They position themselves as the friendly high-end people who have your best interest at heart. It's all about the story and the angle you take and how much it resonates with the people you're selling to.