You may want to try visiting the offices of the Realtors who list these properties, and especially, introduce yourself to the office manager. We are bombarded by all types of service people, in every area relating to real estate. A personal visit makes you stand out from the crowd and lets the agents know you are really interested in earning their business.
Social Media is another tool that is largely untapped by the real estate service industries, get your name and face out here on the web and make it easy for people to find you. I may loose your card, but if you are in front of me on a regular basis online, the odds are much greater that I will call you when I need your services.