You might want to first promote your booth to your existing customers (via e-mail or direct mail) with offers that speak to those people about their specific needs and the ways in which your products, goods, and services can meet or exceed those needs.
In this kind of communication it's wise to provide an offer that will tempt people to visit your booth—perhaps through some kind of prize draw for something of value (an iPad, an Amazon Kindle, or an iTunes gift card).
It's there, at the point of interaction on the floor at the booth that you can strengthen the bond between you as the service provider and your customer as brand advocate.
For new or soon to be customers, other ways to connect with them might be through relevant online forums, or through mail drops to purchased lists. But if you're going to do this, your message needs to be directed SPECIFICALLY at the point of pain or need of that person.
Your message must address the pressing concern of the prospect and it needs to talk to the prospective customer about their need and about their desired outcome. The more you can help your prospect envision their life as it will be as a direct result of using (or of having used) your products, goods, and services, the more you'll build their sense of anticipation.
I hop this helps. Good luck to you.
Princeton, NJ, USA