There are limited dimensions you can compete on when it comes to new brands, especially since a great product is now table stakes. Yes, core product innovation can still win. But it isn't a guarantee by itself.
The first dimension after product is price. A lot of commercial founders gravitate here. But price leadership is generally a bad business model. To win online, you have to be able to outcompete on acquisition cost ("the new rent"). Thin margins make it much, much harder to outspend your competitors. Even if you have good repeat purchase rates, that potentially means floating a long payback period. And the costs of capital, especially in the beginning, are high. A low price may also be bad for your brand.
The second dimension, which a lot of brand/design founders pick, is exclusivity. But limiting access to the product is fairly diametrically opposed to building a very large business. As I like to say to a friend who works in luxury business: the only good thing you do in the world is to make rich people slightly less rich. Which is a joke, but also not. We are about democratizing access.
That brings us to the last and really the only dimension you should compete on, which is customer experience. Start with what's wrong with the shopping experience for your product or service vertical. And then rethink that experience completely. How can you make it an amazing experience? Think 7-star customer service.
The rules of the game are changing.