In a new start up, you are likely to have only a few customers. They are going to be the people who tell their friends about this new business they [shopped/bought/consulted]. How you treat and interact with them will make a significant difference in the growth of your company.
The thing is, they are going to want features, additional items or changes to your product or services - requests you may be loathe to fill. Since they are your first customers, you might feel you have to satisfy all those requests. But what if those requests conflict with your vision of where your company is going and what your customers will look like.
So you find yourself in a quandary: either make the changes the first customers request, or risk losing their business (sticking to your view of what should be the business) and losing those first customers.
How to respond?
Make the customer feel they are part part of your business. We all want to be the person who knows of the little known shop or great new restaurant. You can inculcate this behavior by creating a great experience to your early customers (even if you say no to their requests). Even if you can't add their new feature request, or change your product mix immediately in your shop, try to get them to participate in the process.
Grocery stores used to do this on occasion. They would have a form to request a special order or special product. If it was available, they could add it to the grocery shelf. I remember our local grocery store used to do that, and then all the special order products would be stuck in the same area. It was very interesting to see what people had requested. But each in a small way created a connection to that customer. Even if they were unable to get it, the participation of the customer itself had value.
Making the first customers count (meaning 'do something for you') can create the relationship you need to get your business rolling.