Small or starting e-shops often make one mistake: they try to promote their brand instead of promoting products. Note that the vast majority of big retailers’ advertisements promote just a very few selected deals, very seldom they run advertisements on their brand. Why? Customers don’t care about your business; they want to solve their business.
No matter what you sell, primarily promote specific products or deals you offer. One specific phone, one specific book bestseller, specific loan offer, etc. Don’t worry, everyone understands that you have thousands of other options. Just get them to your shop or web.