To move your business up market you need to look at two approaches. Either you identify and cultivate wealthier prospects, meaning you go to them, or you insert yourself into their world and meet them socially, gradually converting social relationships into business relationships.That's the "they come to you" approach.
Let's start with the first approach, you going to them. You could start by identifying high-paying professions in your market. If you do an Internet search for "Bureau of Labor Statistics, along with the word salary and your city, you should find a report it issues on what different professions pay in your market.
Next, visit a website like searchsystems.net, which is a clearinghouse for about 55,000 public access databases. You can look up professional licensing information by state. Here's why this works: Many years ago, about one in 20 professions required a license. Today it's about one in three. In most states you can easily get a list of the people in your area licensed to work in one of those high-earning professions you just identified. You can market to these names, run them through LinkedIn to determine who knows who or just show names to clients employed in the same field and ask for an introduction.